Although the deadline has passed to register to vote in next month’s general election, Boulder County officials said Tuesday that some people still have work to do before casting ballots.

So far, about 1,700 registration forms have been identified by the Clerk and Recorder’s Office as not being completed according to Colorado law.

Those people — who didn’t check an appropriate box, missed a signature or otherwise failed to fill out the form completely — will still be allowed to vote come Nov. 4, so long as they return a letter being mailed out over the next two weeks.

The letters will contain a message including what was missing, how to fix it and a pre-paid return envelope, said clerk and recorder spokeswoman Jessie Cornelius.

“We encourage people to do it as soon as possible, but they do have until Election Day,” she said.

The letters will all be mailed out by Oct. 19, Cornelius said.

Anyone who receives a letter but doesn’t send it back by Oct. 27 is asked to instead bring the letter in person to the clerk’s office at 1750 33rd St. in Boulder.

Cornelius said registrations filled out at the clerk’s office, sent by mail or completed at independent voter registration drives are all processed the same, and letters will be sent to anyone found to have missing information.

Still, election officials are asking voters to check their registration status online at www.voteboulder.org.

On Monday, the last day to register for the general election, the Boulder clerk’s office was flooded with residents eager to vote next month. County employees helped hundreds of people move through the registration process, Cornelius said.

“It was extremely busy,” she said. “The phones were ringing all day. It was pretty much constant, with people coming in all day.”

Final tallies on last-day registrations weren’t available Tuesday, but officials said at least 15,000 forms requesting changes of address or mail-in ballots still needed to be recorded into the computer system.