As you probably already know (and as this map confirms), Montana has no chance of gaining a seat in the U.S. House when redistricting begins in 2011. The big winners, according to Polidata projections (.pdf), will be the south and southwest, which in theory will benefit Republicans.
Nevada is expected to pick up a seat, which means Montana’s lone U.S. Rep. Denny Rehberg, who now has the second-highest number of constituents in Congress behind Nevada’s 3rd District, will take the top spot. Rehberg, of course, represents the entire population of Montana, or about 960,000 people.