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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 are approximate and for reference only. ISO/RTO and balancing authority boundaries are sourced from electricitymaps (MIT license). NERC region boundaries are approximate by NERC's own acknowledgment. Utility planning area data has coverage gaps in parts of the central US.
Renewable % (Step 7) figures are 2024 data sourced from ISO State of the Market reports and annual filings published in 2025. Renewables include wind, solar, hydro, geothermal, and biomass.
Sources: electricitymaps/electricitymaps-contrib (MIT) · ecoinvent/nerc-regions (CC0) · HIFLD Open Data (FERC 714, EIA 860/861)
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. Every generator inside an interconnection stays in lockstep with every other. Power flows freely within an interconnection, but you cannot move it between them the way you'd plug in an extension cord. Moving power between interconnections requires special conversion equipment, and only a handful of those links exist. This is why Texas froze independently during the 2021 winter storm. 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. Click any region to learn more.
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. Every generator inside an interconnection stays in lockstep with every other. Power flows freely within an interconnection, but you cannot move it between them the way you'd plug in an extension cord. Moving power between interconnections requires special conversion equipment, and only a handful of those links exist. This is why Texas froze independently during the 2021 winter storm. 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. Click any region to learn more.