Henry L. O'Brien (c. 1869 – February 8, 1935) was an American politician from New York.
O'Brien was elected on January 9, 1930, to the New York State Senate (9th D.) to fill the vacancy caused by the resignation of Charles E. Russell. The State Board of Canvassers rejected a contest by his defeated Republican opponent William Koch, and certified O'Brien's election on January 20. He took his seat the same day, and remained in the State Senate until his death in 1935, sitting in the 153rd, 154th, 155th, 156th, 157th and 158th New York State Legislatures.
- O'BRIEN ELECTED SENATOR in the New York Times on January 10, 1930 (subscription required)
- RULES O'BRIEN ELECTED in the New York Times on January 21, 1930 (subscription required)
- HENRY O'BRIEN DIES; WAS IN STATE SENATE in the New York Times on February 9, 1935 (subscription required)
- Henry L. O'Brien, State Senator, Dies At Home of Niece newspaper clipping with portrait, at The East New York Project
|New York State Senate|
Charles E. Russell
| New York State Senate
Jacob H. Livingston