This temple is the lone temple for Bheesma Pitamah in the world. As he is a son of Ganga, his temple is also in the banks of Ganga. This temple was built in 1961.
Some proclaim that he is Lord Shiva’s incarnation and is one of the Ashta vasu’s.
Some proclaim that his lineage as follows
Lord Anjaneya (an incarnation of Shiva)
Sage Durvasa (an incarnation of Shiva)
Bheesma Pitamah
Saint Trailinga Swamigal (Walking Lord Shiva of Varanasi)
etc..
Details about the temple are given in the link below
http://timesofindia.indiatimes.com/city/allahabad/Lone-temple-of-Bhishma-Pitamah-exists-in-Allahabads-Daraganj/articleshow/42896177.cms