The headquarters of Ghadar Movement/Party were at

The Ghadar Movement, also known as the Pacific Coast Hindustan Association, was founded in 1913 by Lala Hardayal and Sohan Singh Bhakna [1]. The party's headquarters were established in San Francisco, California, and were famously known as Yugantar Ashram [3]. This location served as the central hub for the movement's revolutionary activities, including the publication of their journal, 'Ghadar', which first appeared on November 1, 1913 [1]. The headquarters initially operated from 436 Hill Street before moving to 5 Wood Street, which is now the site of the Gadar Memorial Hall. San Francisco was chosen due to its significant Indian immigrant population and its role as a base for activists seeking to liberate India from British colonial rule through armed rebellion. While the movement had roots in Portland and Astoria, the official headquarters remained in San Francisco.

Sources

1. [1] History , class XII (Tamilnadu state board 2024 ed.) > Chapter 3: Impact of World War I on Indian Freedom Movement > Morley > p. 35
2. [3] https://www.cgisf.gov.in/page/gadar-memorial-hall/