California cities dominate the list where $400,000 buys the least home space, with San Francisco offering about 393 sq. ft. and San Jose around 480 sq. ft. Other coastal cities like Irvine, San Diego, Los Angeles, and Long Beach also provide limited space under this budget. In contrast, Midwestern and Southern cities offer significantly more space, with Detroit providing roughly 5,000 sq. ft. and Memphis over 2,800 sq. ft. The disparity highlights regional affordability differences.