Land raised more than $1 million from individual donors and gave her campaign approximately $1 million, according to a release from her campaign. Land has said she's willing to spend up to $5 million of her own money on the race. The big fundraising haul is a sign she could be a formidable candidate.

"This report shows broad support from over 1,500 supporters who are tired of the broken government in Washington, D.C., and ready for a leader with a record of efficient and effective government," said campaign senior advisor John Yob. 

"Congressman Peters has been part of the problem in Washington, D.C., rather than part of the solution in Michigan, and the high percentage of funds that he has received from political action committees is alarming."

Polling has shown a tight race between Land and Peters, though most observers believe he starts the race with an upper hand in the slightly Democratic-leaning state.

Michigan Democrats knocked Land for her self-funding boost.

"Whether it's fundraising off Syria or rooting for the federal shutdown, Terri Land has made it clear she'd rather pander to the Tea Party than do what's right for Michigan middle class families," said Michigan Democratic Party spokesman Joshua Pugh. "Michiganders have a message for Land — our U.S. Senate seat is not for sale, whether from Land's pocket or the dark money she's urging into the race. Michigan needs an independent voice like Gary Peters, who has proven that our middle class families and small businesses can count on him."

The two are running to replace Sen. Carl LevinCarl Milton LevinHow House Republicans scrambled the Russia probe Congress dangerously wields its oversight power in Russia probe The Hill's Morning Report — Sponsored by CVS Health — Trump’s love-hate relationship with the Senate MORE (D-Mich.), who is retiring.

This post was updated at 5:20 p.m.