The Freedom Shield drills are set for March 9-19, according to the announcement on Wednesday.
North Korea has long described the allies' joint exercises as invasion rehearsals and used them as a pretext to dial up its own military demonstrations and weapons testing activity.
The allies say the exercises are defensive in nature.
The announcement came as North Korea holds a major political conference where authoritarian leader Kim Jong-un is expected to outline his key domestic, foreign policy and military goals for the next five years.
North Korean state media has not so far reported any direct comments by Mr Kim on relations with Washington and Seoul at the ruling Workers' Party congress, which began last week.
Based on recent public comments, experts say Kim could use the congress to further entrench his hardline stance towards South Korea, reiterate calls for Washington to drop its demand for denuclearisation as a precondition for renewed talks, and announce steps to simultaneously strengthen and integrate his nuclear and conventional forces.
Freedom Shield is one of two "command post" exercises that the allies conduct each year; the other is Ulchi Freedom Shield, held in August.
The drills are largely computer-simulated and designed to test the allies' joint operational capabilities while incorporating evolving war scenarios and security challenges.
As usual, the March drill will be accompanied by a field training program called Warrior Shield to enhance "training realism and combat readiness", Col Ryan Donald, public affairs director of US Forces Korea, told a news conference.
South Korean and US officials have not said how many troops will take part.
The exercises typically involve thousands.
There has been speculation that the allies are seeking to tone down the drills to create conditions for dialogue with North Korea.
Liberal South Korean President Lee Jae-myung has expressed a desire for inter-Korean engagement, and some of his top officials have voiced hope that US President Donald Trump's expected visit to China in late March or April could open the door to renewed talks between Washington and Pyongyang.
