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U.S. Electric Utility Directory

Every electric utility in the United States that reports to the Energy Information Administration, with its ownership type, grid operator, balancing authority, customers and the counties it serves. Search by state, ISO or name, or click a county to see who serves it.

Compiled October 31, 2026 from EIA Form 861, data year 2025. 3,405 entities, 11,758 utility-to-county links.

Entities listed3,405Every EIA-861 and 861S filer
Retail utilities3,065Investor-owned, co-op, municipal, public power, CCA
County links11,758Utility to county, with FIPS codes
Jurisdictions5650 states, DC and five territories

Map of utility service territories and ISO footprints

Each county takes the color of the grid operator serving most of its customers. Pick a state, an ISO or a type of utility, search for a utility by name or EIA ID, or click a county to list the utilities that serve it.

Loading the map of 3,138 counties…

CAISOERCOTSPPMISOPJMNYISOISO-NEWest (no ISO)Southeast (no ISO)Alaska (no ISO)Hawaii (no ISO)Other (no ISO)

Electric utilities by state

Each state page lists every utility serving the state with its EIA ID, ownership type, ISO or region, balancing authority, customers and counties served, plus a county-by-county table of which utilities serve each county.

Utilities by ISO, RTO and region

Retail utilities assigned to each grid operator, from their EIA balancing authority in each state. A utility operating in two markets is counted in both.

Retail-serving utilities by grid operator
ISO or regionOperatorUtilitiesCounties (majority)Retail customersStates
CAISOCalifornia Independent System Operator765316,176,916CA, NV
ERCOTElectric Reliability Council of Texas1171563,852,098TX
SPPSouthwest Power Pool5434667,602,082AR, CO, IA, KS, LA, MN, MO, MT, NE, NM, ND, OK, SD, TX, WY
MISOMidcontinent Independent System Operator79079823,106,021AR, IL, IN, IA, KS, KY, LA, MI, MN, MS, MO, ND, OK, SD, TN, TX, WI
PJMPJM Interconnection32250630,172,997DE, DC, IL, IN, KY, MD, MI, NJ, NY, NC, OH, PA, TN, VA, WV
NYISONew York Independent System Operator64628,377,401NJ, NY, PA
ISO-NEISO New England96677,465,431CT, ME, MA, NH, NY, RI, VT
West (no ISO)Western utilities outside an RTO (balancing authorities such as BPA, PacifiCorp, APS, SRP, NV Energy)38335719,839,865AZ, CA, CO, ID, MT, NE, NV, NM, OK, OR, SD, TX, UT, WA, WY
Southeast (no ISO)Southeastern utilities outside an RTO (Southern Company, TVA, Duke, Santee Cooper, Florida utilities)49961830,789,884AL, FL, GA, KY, MS, NC, SC, TN, VA
Alaska (no ISO)Alaska, isolated systems670308,503AK
Hawaii (no ISO)Hawaii, island grids40496,723HI
Island grid (no ISO)Puerto Rico and other territories501,609,883AS, GU, MP, PR, VI
Other (no ISO)Other areas outside an RTO125551,093,121AR, IL, IN, IA, KS, ME, MA, MO, NE, NY, OH, OK, SD, TX

Utilities by ownership type

All EIA-861 entities by ownership
TypeEntitiesCustomersStates
Investor-owned175103,061,03750
Cooperative86020,192,81747
Municipal1,82016,767,14349
Public power1847,097,00944
Community choice263,699,1992
Marketers and other34018,306,36339
Total3,405169,123,56856

Public power combines public power districts, state authorities, federal entities and joint action agencies. Marketers and other covers retail and wholesale power marketers, transmission-only companies and behind-the-meter providers. Customer counts for marketers include retail choice customers who also appear under their delivery utility.

The 100 largest U.S. electric utilities by customers

Retail customers across all states served
RankUtilityEIA IDTypeISO or regionStatesCustomersCounties
1Pacific Gas & Electric Co.PG&E14328Investor-ownedCAISOCA5,471,78650
2Southern California Edison CoSouthern California Edison17609Investor-ownedCAISOCA5,111,83816
3Florida Power & Light CoFlorida Power & Light (NextEra)6452Investor-ownedSoutheast (no ISO)FL4,961,28835
4Commonwealth Edison CoComEd (Exelon)4110Investor-ownedPJMIL4,021,99124
5Consolidated Edison Co-NY IncCon Edison4226Investor-ownedNYISONY3,482,6636
6Virginia Electric & Power CoDominion Energy Virginia / North Carolina19876Investor-ownedPJMNC, VA, WV2,601,179124
7Duke Energy Carolinas, LLCDuke Energy Carolinas5416Investor-ownedSoutheast (no ISO)NC, SC2,596,44663
8Georgia Power CoGeorgia Power (Southern Co)7140Investor-ownedSoutheast (no ISO)GA2,536,685155
9Public Service Elec & Gas CoPSE&G15477Investor-ownedPJMNJ2,266,38717
10DTE Electric CompanyDTE Electric5109Investor-ownedMISOMI2,201,18419
11FirstEnergy Pennsylvania Electric Co66101Investor-ownedPJMNY, PA2,097,10357
12PacifiCorpPacifiCorp (Rocky Mountain Power UT/WY/ID; Pacific Power OR/WA/CA)14354Investor-ownedWest (no ISO)CA, ID, OR, UT, WA, WY1,899,84590
13Consumers Energy CoConsumers Energy4254Investor-ownedMISOMI1,827,15962
14Duke Energy Florida, LLCDuke Energy Florida6455Investor-ownedSoutheast (no ISO)FL1,801,55133
15Niagara Mohawk Power Corp.National Grid NY (Niagara Mohawk)13573Investor-ownedNYISONY1,679,05741
16PECO Energy CoPECO (Exelon)14940Investor-ownedPJMPA1,640,8126
17Duke Energy Progress - (NC)Duke Energy Progress3046Investor-ownedSoutheast (no ISO)NC, SC1,580,64969
18Ohio Power CoAEP Ohio14006Investor-ownedPJMOH1,484,32161
19Alabama Power CoAlabama Power (Southern Co)195Investor-ownedSoutheast (no ISO)AL1,480,47559
20Public Service Co of ColoradoXcel Energy – Colorado15466Investor-ownedWest (no ISO)CO1,478,99256
21Northern States Power Co - MinnesotaXcel Energy – NSP-Minnesota13781Investor-ownedMISOMN, ND, SD1,478,54467
22Puerto Rico Electric Pwr AuthorityPuerto Rico Electric Power Authority (LUMA operates T&D)15497State authorityIsland grid (no ISO)PR1,473,2300
23San Diego Gas & Electric CoSDG&E (Sempra)16609Investor-ownedCAISOCA1,453,1792
24PPL Electric Utilities CorpPPL Electric Utilities14715Investor-ownedPJMPA1,440,55933
25Los Angeles Department of Water & PowerLos Angeles Dept of Water & Power11208MunicipalWest (no ISO)CA1,435,5722
26NSTAR Electric CompanyEversource (NSTAR Electric, MA)54913Investor-ownedISO-NEMA1,428,06711
27Massachusetts Electric CoNational Grid MA (Massachusetts Electric)11804Investor-ownedISO-NEMA1,317,66112
28Baltimore Gas & Electric CoBGE (Exelon)1167Investor-ownedPJMMD1,290,9318
29Connecticut Light & Power CoEversource (Connecticut Light & Power)4176Investor-ownedISO-NECT1,251,0528
30Arizona Public Service CoArizona Public Service803Investor-ownedWest (no ISO)AZ1,235,45114
31Union Electric Co - (MO)Ameren Missouri19436Investor-ownedMISOMO1,223,59564
32Ameren Illinois CompanyAmeren Illinois56697Investor-ownedMISOIL1,220,68081
33Puget Sound Energy IncPuget Sound Energy15500Investor-ownedWest (no ISO)WA1,149,7818
34Long Island Power AuthorityLong Island Power Authority (PSEG Long Island operator)11171State authorityNYISONY1,131,7763
35Jersey Central Power & Lt CoJersey Central Power & Light (FirstEnergy)9726Investor-ownedPJMNJ1,131,19013
36Wisconsin Electric Power CoWe Energies (WEC)20847Investor-ownedMISOIL, MI, WI1,130,43540
37Entergy Louisiana LLCEntergy Louisiana11241Investor-ownedMISOLA1,083,56060
38Salt River Project16572Public power districtWest (no ISO)AZ1,060,0163
39Ohio Edison CoOhio Edison (FirstEnergy)13998Investor-ownedPJMOH1,050,12936
40Appalachian Power CoAppalachian Power (AEP)733Investor-ownedPJMVA, WV955,57755
41San Diego Community Power64289Community choice aggregatorCAISOCA939,5470
42Nevada Power CoNV Energy (Nevada Power)13407Investor-ownedWest (no ISO)NV934,3702
43New York State Elec & Gas CorpNYSEG (Avangrid)13511Investor-ownedNYISONY898,68844
44Portland General Electric CoPortland General Electric15248Investor-ownedWest (no ISO)OR888,1237
45Potomac Electric Power CoPepco (Exelon)15270Investor-ownedPJMDC, MD875,8773
46Oklahoma Gas & Electric CoOG&E14063Investor-ownedSPPAR, OK845,49854
47City of San Antonio - (TX)CPS Energy (San Antonio)16604MunicipalERCOTTX832,5908
48Duke Energy Indiana, LLCDuke Energy Indiana15470Investor-ownedMISOIN830,27071
49MidAmerican Energy CoMidAmerican Energy (BHE)12341Investor-ownedMISOIA, IL, SD779,80360
50Tampa Electric CoTampa Electric (Emera)18454Investor-ownedSoutheast (no ISO)FL763,5714
51Cleveland Electric Illum CoThe Illuminating Co (FirstEnergy)3755Investor-ownedPJMOH751,9799
52Dominion Energy South Carolina, IncDominion Energy South Carolina17539Investor-ownedSoutheast (no ISO)SC726,67926
53Duke Energy Ohio IncDuke Energy Ohio3542Investor-ownedPJMOH718,09923
54Entergy Arkansas LLCEntergy Arkansas814Investor-ownedMISOAR, MO, TN711,93871
55Sacramento Municipal Util DistSMUD16534Public power districtWest (no ISO)CA627,8452
56Central Maine Power CoCentral Maine Power (Avangrid)3266Investor-ownedISO-NEME618,57214
57Duquesne Light CoDuquesne Light5487Investor-ownedPJMPA599,7173
58Indiana Michigan Power CoIndiana Michigan Power (AEP)9324Investor-ownedPJMIN, MI595,19231
59Atlantic City Electric CoAtlantic City Electric (Exelon)963Investor-ownedPJMNJ554,8828
60Public Service Co of OklahomaPublic Service Co of Oklahoma (AEP)15474Investor-ownedSPPOK554,49946
61Kentucky Utilities CoKentucky Utilities (PPL)10171Investor-ownedSoutheast (no ISO)KY, TN, VA552,92384
62Idaho Power CoIdaho Power9191Investor-ownedWest (no ISO)ID, OR551,45529
63Kansas City Power & Light CoEvergy Missouri Metro (formerly KCP&L)10000Investor-ownedSPPKS, MO548,39825
64Southwestern Electric Power CoSWEPCO (AEP)17698Investor-ownedSPPAR, LA, TX536,15550
65Public Service Co of NMPNM (TXNM Energy)15473Investor-ownedWest (no ISO)NM526,34618
66Delmarva PowerDelmarva Power (Exelon)5027Investor-ownedPJMDE, MD525,19413
67Dayton Power & Light CoAES Ohio (formerly Dayton Power & Light)4922Investor-ownedPJMOH523,49224
68Public Service Co of NHEversource (PSNH)15472Investor-ownedISO-NENH517,34910
69The Narragansett Electric CoRhode Island Energy (PPL)13214Investor-ownedISO-NERI497,1335
70Indianapolis Power & Light CoAES Indiana (formerly Indianapolis Power & Light)9273Investor-ownedMISOIN495,35220
71Interstate Power and Light CoAlliant Energy – Interstate Power & Light (IA)9417Investor-ownedMISOIA490,24584
72Austin Energy1015MunicipalERCOTTX487,9292
73Wisconsin Power & Light CoAlliant Energy – Wisconsin Power & Light20856Investor-ownedMISOWI474,70434
74Northern Indiana Pub Serv CoNIPSCO (NiSource)13756Investor-ownedMISOIN471,89120
75JEAJEA (Jacksonville)9617MunicipalSoutheast (no ISO)FL467,0844
76City of Seattle - (WA)Seattle City Light16868MunicipalWest (no ISO)WA461,5231
77Entergy Texas Inc.Entergy Texas55937Investor-ownedMISOTX453,04327
78Entergy Mississippi LLCEntergy Mississippi12685Investor-ownedMISOMS450,06046
79Wisconsin Public Service CorpWisconsin Public Service (WEC)20860Investor-ownedMISOWI444,64722
80Tucson Electric Power CoTucson Electric Power24211Investor-ownedWest (no ISO)AZ426,4512
81El Paso Electric CoEl Paso Electric5701Investor-ownedWest (no ISO)NM, TX422,2817
82Marin Clean Energy56692Community choice aggregatorCAISOCA416,8970
83City of Memphis - (TN)Memphis Light, Gas & Water12293MunicipalSoutheast (no ISO)TN416,4331
84Louisville Gas & Electric CoLouisville Gas & Electric (PPL)11249Investor-ownedSoutheast (no ISO)KY411,7119
85The Potomac Edison CompanyPotomac Edison (FirstEnergy, MD/WV)15263Investor-ownedPJMMD, WV411,67115
86Nashville Electric Service13216MunicipalSoutheast (no ISO)TN402,9897
87Monongahela Power CoMon Power (FirstEnergy, WV)12796Investor-ownedPJMWV391,90134
88Southwestern Public Service CoXcel Energy – SPS (TX/NM)17718Investor-ownedSPPNM, TX391,71651
89Avista CorpAvista20169Investor-ownedWest (no ISO)ID, MT, WA387,66219
90Westar Energy IncEvergy Kansas Central (formerly Westar)22500Investor-ownedSPPKS381,42041
91Rochester Gas & Electric CorpRG&E (Avangrid)16183Investor-ownedNYISONY381,3267
92Omaha Public Power District14127Public power districtSPPIA, NE380,30715
93NorthWestern Energy LLC - (MT)NorthWestern Energy (MT)12825Investor-ownedWest (no ISO)MT, WY372,82336
94PUD 1 of Snohomish CountySnohomish County PUD17470Public power districtWest (no ISO)WA350,4672
95Pedernales Electric Coop, Inc14626CooperativeERCOTTX348,58724
96Sierra Pacific Power CoNV Energy (Sierra Pacific)17166Investor-ownedWest (no ISO)NV347,19914
97United Illuminating CoUnited Illuminating (Avangrid)19497Investor-ownedISO-NECT336,0082
98Kansas Gas & Electric CoEvergy Kansas South (formerly KG&E)10005Investor-ownedSPPKS330,19724
99KCP&L Greater Missouri Operations Co.Evergy Missouri West (formerly KCP&L GMO)12698Investor-ownedSPPMO326,62731
100The Toledo Edison CoToledo Edison (FirstEnergy)18997Investor-ownedPJMOH310,97910

Texas transmission and distribution utilities (Oncor, CenterPoint Energy Houston Electric, AEP Texas and TNMP) deliver power to millions of ERCOT customers who buy from retail providers. EIA records those customers under the retail providers, so the delivery utilities carry no count here and do not appear in this ranking. Generation-only and transmission-only companies are likewise listed without customers.

What the directory contains

Entities
3,405 electric utilities, retail marketers and other entities that file with EIA, each with its EIA utility ID
Utility–state records
4,349 rows: one per utility per state it serves
Utility–county links
11,758 links between 2,900 utilities and 3,138 counties, identified by name and 5-digit FIPS code
Ownership type
Investor-owned, cooperative, municipal, public power district, state, federal, joint action, community choice aggregator, retail power marketer, wholesale marketer, transmission-only, behind-the-meter
Grid operator
ISO/RTO for each utility in each state (CAISO, ERCOT, SPP, MISO, PJM, NYISO, ISO-NE) or its non-RTO region, derived from EIA balancing authority codes
Balancing authority
EIA balancing authority codes per utility per state
Customers
Retail customer counts per utility per state
Coverage
All 50 states, the District of Columbia, Puerto Rico, Guam, the U.S. Virgin Islands, American Samoa and the Northern Mariana Islands: 56 jurisdictions

Download the dataset

One row per utility per state (4,349 rows): EIA utility ID, EIA and brand names, ownership type, ISO or region, balancing authority codes, retail customers, counties served with 5-digit FIPS codes, and whether the utility started reporting after 2018.

Download CSV (593 KB)

Sources

Which utilities exist comes from the U.S. Energy Information Administration’s Form EIA-861 and EIA-861S, data year 2025 (final release, October 7, 2026), read directly from eia.gov. County service territories, balancing authority codes and customer counts come from EIA-861 for 2018, the latest year compiled at county level for this directory; utilities that started reporting after 2018 carry their 2025 values. County boundaries are U.S. Census cartographic boundaries (us-atlas 3.0, Albers USA projection).

Free to use with attribution: “Discovery Energy U.S. Electric Utility Directory, from U.S. EIA Form 861.”

Questions about the directory

What is the Discovery Energy U.S. Electric Utility Directory?

A dataset and map of every electric utility, retail power marketer and related entity that reports to the U.S. Energy Information Administration: 3,405 entities in data year 2025, including 3,065 retail-serving utilities. For each it gives the EIA utility ID, ownership type, states served, ISO/RTO or region, balancing authority, retail customers and the counties it serves, 11,758 utility-to-county links in all.

How many electric utilities are there in the United States?

EIA data year 2025 lists 3,405 entities. Of these, 3,065 serve retail customers directly: 175 investor-owned utilities, 860 cooperatives, 1,820 municipal utilities, 184 public power districts, state and federal entities, and 26 community choice aggregators. The remaining 340 are retail and wholesale power marketers, transmission-only companies and behind-the-meter providers.

How do I find which electric utility serves a county?

Use the map: click a county to list every utility EIA records as serving it, or open the state page, which has a county-by-county table. Many counties are served by more than one utility, for example an investor-owned utility in towns and a cooperative in rural areas.

How is each county assigned to an ISO or RTO?

Each utility is assigned to the grid operator of its balancing authority in each state. A county takes the ISO that serves most of its customers, estimated by spreading each utility’s customers in a state evenly across the counties it serves. Counties split between operators, such as parts of Texas, Missouri and Louisiana, show the larger share.

How current is the data?

The list of entities is from EIA-861 data year 2025, released October 7, 2026. County service territories, balancing authority codes and customer counts are from EIA-861 2018 for utilities that existed then, and from 2025 for utilities formed since. ISO assignments predate the Southwest Power Pool’s 2026 western RTO expansion. The directory was compiled on October 31, 2026.

Can I download the directory?

Yes. The full dataset is a CSV file with one row per utility per state (4,349 rows), including EIA utility IDs, county names and 5-digit county FIPS codes.

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