Cloud regions cluster in a small number of US locations that share few obvious characteristics. What they have in common is electricity, and the ability to deliver a great deal of it.
Power is the dominant operating cost
A large facility consumes electricity continuously at industrial scale, and over a multi-year life that expense exceeds the cost of the building itself.
Small differences in the per-unit rate therefore compound into very large differences in total cost, which makes cheap power the first filter in site selection.
Regions with hydroelectric generation, abundant wind, or surplus baseload capacity consistently attract facilities for this reason alone.
Available capacity matters as much as price
A campus may require more power than an entire town, and the local grid must be able to deliver it without years of transmission construction.
Where capacity is constrained, utilities have begun queuing new connections, which delays projects regardless of what the operator is willing to pay.
Proximity to existing high-voltage transmission is consequently a stronger predictor of where a facility appears than population or customer location.
Climate determines the cooling method
Heat removal is the second largest energy consumer, and cooler, drier climates allow outside air to do much of the work for a large part of the year.
Water-based cooling is efficient but consumes supply that may be contested locally, which has become a significant factor in siting decisions in dry regions.
Warmer sites can be built and operated, but they carry a permanent efficiency penalty that shows up in the facility's energy overhead ratio.
Fiber routes narrow the remaining options
A region must connect to long-haul networks with diverse physical paths, since a single fiber route creates a failure mode no amount of local redundancy fixes.
Existing routes largely follow railroads and interstate corridors laid out long before, which constrains where good connectivity is available at reasonable cost.
Latency to population centers matters for customer-facing services, but it is a weaker constraint than it sounds, since a few milliseconds is acceptable for most workloads.
Local incentives decide among qualified sites
States and counties compete with property and sales tax abatements tied to investment and job commitments, which can shift the economics between otherwise similar locations.
Because these facilities employ relatively few people for their capital cost, the negotiations often center on infrastructure contributions rather than employment.
The result is a map that reflects utility rates, transmission and tax policy far more than it reflects where the data's owners actually live.