The spread of Buddhism

The silk road contributed to the spread of Buddhism.

India and Nepal had Buddhism from 588 BCE, my guess of when the Buddha became enlightened.

Buddhism comes to Sri Lanka in the 3rd Century.

Padmasambhava goes to Tibet in 749 ACE. Buddhism will perhaps have come before that. So too with Sakkhim, Bhutan and Bangladesh. Probably with Ashoka in 3rd century. 

Buddhism gets to Myanmar in the 3rd century from Ashoka.

Thailand thinks they got it in 3rd century from Ashoka. 

Cambodia: Maybe Ashoka in 3rd century, but definitely 4th century. You can see the transition from Hindu to Buddhism in Angkor Wat.

Vietnam also guesses 3rd century. 

China: The first documented translation of Buddhist scriptures into Chinese occurs in 148 CE with the arrival of the Parthian prince-turned-monk, An Shigao.

Korea:  Buddhism entered the Korean peninsula in the 4th century.

Japan probably got Buddhism in 6th century. Kukai brings Vajrayana in 9th century, came to USA in 1913.

USA: Buddhism came to the North American continent in 1800's with Chinese immigrants, 200-250 years ago. In 1965, monks from Sri Lanka established the Washington Buddhist Vihara in Washington, DC, the first Theravada monastic community in the United States. Were the Native Americans descendents of Buddhist? The migration happened before the spread of Buddhism.

Maybe it gets to Iran in 2nd century. Before that in Pakistan and Afghanistan. 

England: Early Buddhist presence could be seen in the 1810s.