Henry Clay Platt (October 22, 1840 – December 16, 1904) was an American lawyer and politician from New York.

[1] Platt attended Huntington Academy and Ashland Hall in West Bloomfield, New Jersey.

[2] In 1863, Platt was elected to the New York State Assembly as a Democrat, representing the Suffolk County 2nd District.

[4] After he left the Assembly, he formed a law practice in New York City with former state senator Robert Christie Jr.

In 1894, he became the United States Attorney to fill a vacancy caused by Edward Mitchell's term expiring.