Henry John Ellenson (born January 13, 1997)[1] is an American professional basketball player for the Wisconsin Herd of the NBA G League.

[1] In August 2014, he was a member of the United States' National Team at the 2014 FIBA Under-17 World Championship in Dubai, scoring 21 points in the quarterfinal game with China.

[7] On April 5, 2016, Ellenson declared for the NBA draft, forgoing his final three years of college eligibility.

[10] On October 26, he made his professional debut in a 109–91 loss to the Toronto Raptors, recording two rebounds in two minutes off the bench.

[11] During his rookie season, Ellenson had multiple assignments with the Grand Rapids Drive, the Pistons' D-League affiliate.

[17] On January 21, 2020, Ellenson was acquired by the Raptors 905 in a sign-and-trade deal with the Long Island Nets.