Pentagon estimate given to Congress covers extended troop presence in the US capital through January 2029.

The extension of the United States National Guard deployment in Washington, DC until January 2029 will cost roughly $1.4bn, according to a Defense Department estimate provided to Congress.

The figure, covering fiscal years 2027-2029, is based on an average of 2,500 Guard members remaining in the capital. The estimate was released in response to questions from Democratic US Senator Elizabeth Warren of Massachusetts.

The deployment has drawn criticism from local officials in Washington who say it infringes on the city’s autonomy, and from Democratic lawmakers who argue it has militarised the capital’s streets at the public’s expense.

“While American families are getting flattened by skyrocketing costs, Donald Trump is spending $1.4bn to keep troops on the streets in Washington for years on end,” Warren said. “The National Guard are not pawns and taxpayer dollars are not a piggy bank for Trump’s political stunts.”

The cost was first reported by The Washington Post.

The National Guard is a reserve military force in the US that can be mobilised for active duty when needed. It responds to domestic emergencies like natural disasters and civil unrest and supports military operations abroad.

The deployment began last summer after US President Donald Trump issued an emergency order that the administration claims was meant to fight crime. Armed Guard troops have since patrolled city streets, supported arrest operations, and taken on other tasks including snow removal and beautification projects.

National Guard numbers swelled to about 5,000 this summer as DC celebrated the 250th anniversary of the signing of the US Declaration of Independence.

The Pentagon said last month that the Guard mission would continue until January 20, 2029, “or until terminated by the president”. The deployment has previously been extended but was due to expire at the end of this year.

US courts have restricted the use of National Guard soldiers in other parts of the country, but their presence continues in the capital, where the president is the direct commander of the DC Guard.

It remains unclear whether US state governors will keep their National Guard members in the capital for the full extension period. As of late July, 4,600 military personnel from DC and 23 states and territories remained in the city, some deployed for security around Independence Day events.

Georgia had roughly 800 personnel in the capital, more than the DC National Guard. Major R Dustin Cole, a spokesperson for the Georgia Air National Guard, said the elevated numbers were temporary but did not specify how many troops would be withdrawn or when.

Hawaii said it will bring home its 27 members later this month after the Freedom 250 Grand Prix. Louisiana will have about 150 Guard members in the city through January 2027.

For some Washington residents, the spending is difficult to justify. Don and Donna Powell, who split their time between Washington and Texas, joined a “Free DC” protest against the continued deployment on Monday.

“They’re everywhere. They’re just hiding wherever it’s shady,” Donna Powell said. The money spent on the deployment, she added, “could be spent on healthcare and food for families that need it, and instead we’re wasting our money”.