Pahasu is a town and a nagar panchayat in Bulandshahr district in the Indian state of Uttar Pradesh.
Pahasu is located at . It has an average elevation of 187 metres (613 feet).
Pahasu was a jagir during British India owned by Nawabs belonging to Lalkhani Muslim"Pahasu" is a large Muslim feudals of Aligarh (UP)."Pahasu" in British India was represented by Old and young party in UP legislative council from years 1909 to 1919.
India census, Pahasu had a population of 17,116. Males constitute 53% of the population and females 47%. Pahasu has an average literacy rate of 48%, lower than the national average of 59.5%: male literacy is 57%, and female literacy is 38%. In Pahasu, 17% of the population is under 6 years of age