Colorado Springs mailed out ballots on Friday for the June 17 special election on whether the city will retain the Karman Line annexation.

The sole question on the ballot is whether the city will keep the 1,867-acre annexation at the core of the proposed Karman Line development, located around 3 miles east of the current city limits. The land was planned to hold around 6,500 single-family homes and a mixed-use commercial district along Bradley Street over the next 25 years.

The series of annexations were approved by the Colorado Springs City Council in January after months of hearings and planning commission reviews. A February petition campaign challenging the development received enough signatures to force the City Council to either reverse the annexation or hold a special election.

A “yes” vote would support the city keeping the Karman Line annexation, while a “no” vote would overturn the annexation.

City Clerk Sarah Johnson said the city website included more details about the Karman Line proposal, the council decisions and the signature campaign.

“It is no pro or con, it is merely information on the history of how we got where we are today with the special election,” Johnson said.

The last time the city held a one-off special election was in August 2012, when city voters approved a plan to lease the Memorial Health System to the University of Colorado system. Just over 44% of the registered voters in the city participated in that election.

The total number of registered voters in Colorado Springs has nearly doubled since 2012, rising from 176,000 electors to more than 330,000 voters who will receive a ballot this year. Johnson said she had no expectations for voter turnout this year but hoped voters would be aware and interested in the single-issue ballot.

Ballots must be returned by mail or in one of the city’s drop boxes by 7 p.m. on June 17. The city will use the same online maps as the City Council elections in April to show voter turnout across the city over the next few weeks.

Johnson said it cost the city around $500,000 to hold this special election.