Iowa is entitled to 6.6 representatives in two districts.
Because the districts will be close to 3.0 representatives, they will have be fairly equal in population. The obvious split is between east and west, and Des Moines will have to be in the western district. Coming from the east, I got to Polk County and had sufficient population for both districts. I played around moving Marshall, Jasper, and Marion to the western district, based on their proximity to Des Moines, but that would have made a more U-shaped eastern district.
The final map places all of I-35 in the western district, assuming a slightly stronger community of interest with Des Moines based on the transportation link. It also results in the denser eastern part of the state having the slightly higher population.
1901 - Eastern Iowa - 3.4 representatives.
1902 - Western Iowa - 3.2 representatives.