Congressional candidate Dan Koh raised a massive amount of money in the first quarter of 2018, pulling in more $900,000 in January, February, March, according to the campaign.

The gargantuan haul means Koh, a one-time chief of staff to Mayor Martin J. Walsh, has raised more than $2.5 million since he began his bid last September for the district anchored in Lowell, Lawrence, and Andover, his campaign said.

“I am grateful for the outstanding support I have received throughout my campaign,” Koh, a Democrat, said in a statement.

A well-stocked bank account could help Koh in a crowded field of several serious contenders for the Democratic nomination. They include: businesswoman Lori Trahan, former US Ambassador to Denmark Rufus Gifford, businessman Beej Das, state Senator Barbara A. L’Italien, and state Representative Juana Matias.


Koh has been boosted by connections from his time at City Hall. The Globe reported last week that Koh raised large sums of money from developers, lawyers, and others who have business before the city.

The 33-year-old also has inroads to several other high-net-worth circles. He is a graduate of Phillips Academy Andover, Harvard College, and Harvard Business School. And Koh worked closely with Arianna Huffington at the Huffington Post.

Official campaign fund-raising reports are due to the Federal Election Commission by mid-April and will be public. The data will provide more information about who the campaign is raising money from and how they are spending the dough.

The primary for the Third District —


— is Sept. 4, the day after Labor Day.

Businessman Rick Green is one of the GOP candidates for the Democratic-leaning seat.

Joshua Miller can be reached at joshua.miller@globe.com.