The 22 women are near completion of their officer training and will be commissioned in coming weeks, the Army has said.
They need to successfully complete the specialty schools and meet the physical requirements before fully qualifying in the fields, USA Today reported.
The military had expected only a small number of women to volunteer for the jobs, at least initially. The Marine Corps said about 200 women a year would likely join newly-opened ground combat positions, including the infantry.
The 22 women are currently in West Point or ROTC and will be commissioned as officers when they graduate. Thirteen will enter the armor field and nine will join infantry.
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Women have served extensively in combat in Iraq and Afghanistan. But until now, they had been prohibited from so-called ground combat fields, which include infantry, armour and Special Forces.
The historic new rules likely place them in leadership roles in occupations that were never open to them before.
The Marine Corps requested an exception for infantry, citing a study that showed infantry units with women did not perform as well as all-male units.
Defence Secretary Ashton Carter, however, denied the request this year, saying there would be no exceptions. The Marines pledged to successfully implement the order.
Carter said standards would not decline as a result of allowing women to enter the ground combat jobs.
Three women have graduated from the Army's Ranger School, a physically demanding small unit leaders' course, since they opened it up to women for the first time last year.