The seven-time Grand Slam winner will make her return to major tennis at Flushing Meadows and is set to become the oldest singles entrant in New York since Renee Richards played the event aged 47 in 1981.
Williams, who triumphed at the US Open in 2000 and 2001, had already been given a wild card by the US Tennis Association for next week's mixed doubles competition.
Venus made her last Grand Slam appearance at Flushing Meadows in 2023 but hasn't won a singles match at the tournament since 2019.
She returned to tennis after a 16-month absence at the DC Open in Washington recently and suggested that she could play at other events.
Williams said: "I'm just here for now, and who knows? Maybe there's more, but at the moment, I'm focused just on this. I haven't played in a year.
"There is no doubt I can play tennis, but obviously coming back to play matches, it takes time to get in the swing of things.
"I definitely feel I'll play well; I'm still the same player. I'm a big hitter, I hit big. This is my brand."
Venus and her sister Serena Williams dominated women's tennis for years and she previously explained how she is very "co-dependent" on her younger sibling, who won 23 major titles during her extraordinary career.
She said: "Yeah, Serena and I are very co-dependent.
"We do the same thing that the other one does. It just goes on and on, it's an endless cycle – even when we were around eight years old and going like, 'I want to do it, too!'
"But it's more of a motivation and when I see her doing great, it's my success. It's also motivating for me and lets me know I also can do that, and that's how you have to look at other people's success."