John Thomas Lenahan (November 15, 1852 – April 28, 1920) was a Democratic member of the U.S. House of Representatives from Pennsylvania.

John T. Lenahan was born in Jenkins Township, Pennsylvania.

He was admitted to the bar in 1873 and commenced practice in Wilkes-Barre, Pennsylvania.

Lenahan was elected as a Democrat to the Sixtieth Congress.

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