Where did hinduism and buddhism spread during ancient indian civilization?

Not sure if you had any answer choices, but through merchants, who traded across the Indian Ocean, Hinduism spread to Southeast Asia, in regions like Vietnam. Buddhism spread along trade routes like the Silk Road. It made its way into East and Southeast Asia in regions like China, Korea and Japan. If you are looking for an area they both spread to it would be Southeast Asia.

Transcontinental railroad was the most effective way to travel.