Right now I'm counting community area population from the census tracts map. Something interesting is how much Near North Side was underestimate in ACS. Near North Side is now the densest community area in Chicago:
https://mtgis-portal.geo.census.gov/...ed2b2fd7ff6eb7
Census 2020 population:
105,481 people - density:
38780 pp/sqmi
ACS 2019 population: 93,318 people - density: 34308 pp/sqmi
Mid-South Side neighborhoods also generally have slightly higher population than estimate from the ACS, some are closer to their 2000 populations