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The US power grid is confusing not because it's poorly designed, but because it has multiple overlapping organizational layers that don't align with each other - markets, reliability regions, utility territories, and physical interconnections all carve the country up differently.
This map steps through those layers one at a time. Use the panel on the left (or the drawer at the bottom on mobile) to navigate.
Boundary disclaimer: All geographic boundaries on this map are approximate and for reference only. ISO/RTO and balancing authority boundaries are sourced from electricitymaps (MIT license) and represent operational approximations, not regulatory-authoritative lines. The three interconnection regions (Step 1) are derived by dissolving balancing authority polygons - no official, publicly accessible interconnection boundary shapefile exists, so the boundaries shown are built up from other known geometries. The true physical boundaries differ from what is shown, particularly along the Western/Eastern divide. NERC region boundaries are approximate by NERC's own acknowledgment. Utility planning area data has coverage gaps in parts of the central US. The EIA and HIFLD data landscape has become less publicly accessible recently - likely a result of federal data policy changes in early 2025. Things that were openly downloadable a year ago may now be behind login walls or simply gone.
Canada and Mexico: The Eastern and Western interconnections extend into Canada (parts of Manitoba, Ontario, and British Columbia among others) and ERCOT extends slightly into northern Mexico. The map shows North American grid boundaries, not US borders.
Renewable % (Step 7) figures are 2024 full-year data sourced from ISO State of the Market reports and annual filings published in 2025. Includes wind, solar, hydro, geothermal, and biomass.
Sources: electricitymaps/electricitymaps-contrib (MIT) · ecoinvent/nerc-regions (CC0)
Three separate electrical systems power the continental US
The continental US does not run on one unified power grid. It runs on three separate electrical systems called interconnections. Each interconnection is essentially one giant synchronized machine: hundreds of power plants all generating electricity at exactly the same frequency (60 cycles per second), perfectly coordinated. Power flows freely within an interconnection, but you cannot move it between them the way you'd plug in an extension cord - it requires special conversion equipment, and only a handful of those links exist. This is why Texas froze independently during the winter of 2021. ERCOT (Electric Reliability Council of Texas) is deliberately isolated from its neighbors, so when Texas generators failed in the cold, no power from neighboring states could flow in to help. Note: these interconnections are not limited to the US. The Eastern and Western interconnections extend into Canada, and ERCOT extends slightly into northern Mexico. The boundaries shown here are approximate - they are derived by combining balancing authority zones, since no single authoritative boundary shapefile or geometry for the interconnections is publicly available. The true physical boundaries differ from what is shown, particularly along the Western/Eastern divide in the central states.
The continental US does not run on one unified power grid. It runs on three separate electrical systems called interconnections. Each interconnection is essentially one giant synchronized machine: hundreds of power plants all generating electricity at exactly the same frequency (60 cycles per second), perfectly coordinated. Power flows freely within an interconnection, but you cannot move it between them the way you'd plug in an extension cord - it requires special conversion equipment, and only a handful of those links exist. This is why Texas froze independently during the winter of 2021. ERCOT (Electric Reliability Council of Texas) is deliberately isolated from its neighbors, so when Texas generators failed in the cold, no power from neighboring states could flow in to help. Note: these interconnections are not limited to the US. The Eastern and Western interconnections extend into Canada, and ERCOT extends slightly into northern Mexico. The boundaries shown here are approximate - they are derived by combining balancing authority zones, since no single authoritative boundary shapefile or geometry for the interconnections is publicly available. The true physical boundaries differ from what is shown, particularly along the Western/Eastern divide in the central states.