Republicans maintained their edge in Iowa, and improved their position in Pennsylvania, but they still lag behind Democrats there by more than 900,000 registered voters.
In Florida, Democrats added more than 25,000 more voters to the rolls than Republicans in the past month, according to new data from the Florida Department of State. The overall Democratic edge is now almost 300,000 --- lower than 2012, but higher than it was this summer.
The registration deadline in Florida was delayed for a week by a federal judge after Hurricane Matthew forced millions to evacuate and displaced many from their homes. Tuesday was the last day to register.
Election officials in Colorado started mailing out ballots to residents Monday, the first presidential election in the state's history where all registered voters automatically get a ballot in the mail.
There are now more registered Democrats than Republicans for the first time in 32 years, according to the Colorado secretary of state. Democrats have improved their position there consistently this year: They turned an 11,600-voter Republican edge to a 6,000-voter deficit for the GOP in three months.
The Democratic registration lead in Nevada swelled by almost 6,000 voters in September, according to data from the Nevada secretary of state. That means there are now 77,000 more registered Democrats than Republicans -- something Clinton and Democrats down the ballot will hope to lean on in November.
New CNN/ORC polling
shows a tight race in Nevada, with Clinton at 46% and Trump at 44%, a race that is within the margin of error. Early voting in the Silver State begins Saturday.
Democrats also managed to hold their registration advantage in North Carolina last month.
Good news for GOP
Republicans added about 12,000 more voters to the rolls than Democrats in Pennsylvania last month. But the GOP is still in the hole: The Democratic advantage is about 906,000 voters, according to the Pennsylvania Department of State.
That edge isn't as large as what President Barack Obama enjoyed in 2012, when it was more than 1.1 million voters. But it is still a significant obstacle for Trump to overcome if he wants to flip the Keystone State red this year -- and Clinton leads in polls there.
In Iowa, Republicans held steady with a lead of about 33,700 registered voters. The registration numbers have been stable in the Hawkeye State this year, which could spell trouble for Democrats.
New numbers were unavailable from New Hampshire, where registered Republicans lead Democrats by 24,000 voters. The small electoral prize -- four electoral votes -- could be pivotal if the race tightens.
The voter rolls change from month to month because people switch parties, move to new states and are scrubbed from the lists when they die. These statistics don't necessarily indicate which party is attracting new voters, but they add context to the political landscape in a particular state.