North Dakota state Rep. Rick Berg (R) disclosed on Monday that his campaign tallied an impressive $483,000 in receipts in the first quarter, the bulk of which was raised after he won the state party’s endorsement on March 20 to take on Rep. Earl Pomeroy (D).

That total includes $380,000 in contributions from individuals and political action committees — $330,000 of which came in the 10-day period following his nomination at the state convention — and a $100,000 personal loan from the candidate.

“In North Dakota numbers, this is huge,” boasted Berg campaign manager Tom Nelson.

The campaign reports that 84 percent of donors are from North Dakota, and 52 percent gave online. Nelson was particularly happy with the fact that 44 percent of donations came in amounts under $100, which he said indicates a strong base of grass-roots support.

Berg will report $324,000 in cash on hand at the end of March. That’s likely to be well behind what Pomeroy will report, after the incumbent ended 2009 with $1.4 million. Berg’s fast start bodes well for his ability to keep pace in the general election.