Rep. Tim Ryan's (D-Ohio) Senate campaign on Wednesday said it had raised a record $2.5 million in the third quarter of the year. 

The haul, which the campaign said is the most-ever for an Ohio Senate candidate in the third quarter of an off-year, brings Ryan's total cash-on-hand to $3.6 million. 

Ryan's campaign said that 96.6 percent of donations were $100 or less and that the campaign brought in ​​22,522 donations in the third quarter alone. 

“Tim’s historic grassroots fundraising is the latest sign of the momentum he’s building to flip Ohio’s open U.S. Senate seat,” Ryan's spokesperson Izzi Levy said in a statement. 

Ryan, who is considered the front-runner in the Democratic primary, is facing progressive Morgan Harper in the state's Democratic Senate primary. Harper announced this week that she brought in $530,000 from 4,117 donors since announcing her candidacy six weeks ago. 

Whoever wins the Democratic primary will take on the winner of the crowded Republican primary in the general election race to fill outgoing Sen. Rob Portman's (R-Ohio) seat.

The GOP side includes former Ohio GOP Chair Jane Timken, former Ohio Treasurer Josh Mandel, venture capitalist and author JD Vance, businessman Mark Pukita, investment banker Mike Gibbons and luxury car dealer Bernie Moreno.

An internal poll of the GOP primary released by WPA Intelligence last week found Mandel leading the crowded field with 37 percent, with Vance trailing in second place at 13 percent. 

The non-partisan Cook Political Report rates the general election race to replace Portman as "lean Republican."