Is Sarva Pitru Amavasya the same as Mahalaya Amavasya?

Yes, Sarva Pitru Amavasya and Mahalaya Amavasya refer to the same day. Sarva Pitru Amavasya is the name used in North Indian and Sanskrit ritual tradition, emphasising the universal scope of ancestral offerings. Mahalaya Amavasya is the name used primarily in Bengal and Maharashtra, emphasising the cosmic dissolution aspect and the transition into Navratri. Both names describe the identical day — the last day of Pitrupaksha.