1/9

1/9 may refer to:

* The fraction one ninth.
* January 9 or 1 September, depending on your date format.
* 1st Battalion 9th Marines, an infantry battalion of the United States Marine Corps.
* U.S. Route 1/9, in New Jersey
* 1 (New York City Subway service)
* 9 (New York City Subway service)