Analysts polled by Reuters had expected an $11 billion deficit for the month and the gap was the latest sign of deterioration in the government's fiscal position.
A strong US job market has appeared to power economic growth this year, an economic setting that tends to help fiscal revenues. Economists suspect some of the economic strength draws from tax cuts that came into effect at the beginning of 2018.
But Washington's accounts have run $319 billion into the red since the fiscal year began in October, compared to a $225 billion deficit over the same period a year earlier.
Wednesday's data was released about a month behind schedule due to 35-day partial government shutdown in December and January.