In an odd move, ASA "announced" 4 additional years of meetings recently (2021-2024). That is, as of three months ago, the official page only listed up to to 2020.
It will not shock you that they are (mostly) repeats.
2017: Montreal
2018: Philly
2019: NYC
2020: San Fran
2021: Chicago
2022: LA
2023: Philly
2024: Montreal
http://www.asanet.org/news-events/meetings/future-annual-meetings