6.13 Redistricting criteria - the case of USA (federal rules - … equal population)
The standard for congressional districts is quite strict, with equal population required “as nearly as is practicable.” - states must make a good-faith effort to draw districts with exactly the same number of people in each district within the state.
Any district with more or fewer people than the average (also known as the “ideal” population) must be specifically justified by a consistent state policy. And even consistent policies that cause a one percent spread from largest to smallest district will likely be unconstitutional.