According to the Des Moines Register, the significant sum marks contributions from more than 2,800 Iowans, including people from all 99 counties in the state.

Braley is the only declared Democratic candidate in the race, and he has the backing of the party establishment and nearly every Democratic name in the state, including retiring Sen. Tom HarkinTom HarkinDemocrats are all talk when it comes to DC statehood The Hill's 12:30 Report Distance education: Tumultuous today and yesterday MORE, whose seat Braley hopes to retain in 2014.

Republicans already have four candidates in the race, and more are expected to enter soon.