Located in Bay Area, Union City has a very diverse population. 

According to the 2010 United States Census: 

• Population: 69,516 (74,559 as of 2019) 
• 99.3% of the population lived in households; 0.6% lived in non-institutionalized group quarters; 0.1% were institutionalized. 
• Homeowner vacancy rate: 1.5%; Rental vacancy rate: 5.3%.  
• 66.6% of the population lived in owner-occupied housing units; 32.7% lived in rental housing units.  

The city maintains the small-town feel while living in the center of the Bay Area, with San Francisco and Silicon Valley just minutes away. Union City is the location of the American Licorice Company's West Coast operations, having moved there in 1971 from San Francisco. Union City is home to three major health care providers: a Kaiser Permanente facility, the Tiburcio Vasquez Health Center, and Washington Hospital's Nakamura Clinic. Union City also has a large number of industrial and shipping companies including R&S Manufacturing, RCD Concrete, Jatco, and EntirelyPets. Several transit systems serve Union City, including AC Transit, the Dumbarton Express, Bay Area Rapid Transit (BART), and the city's own Union City Transit. New Haven Unified School District serves the cities of Union City and Hayward (south). The district consists of seven (K-5) elementary schools, two (6-8) middle schools, one comprehensive high school and one adult/K-12 independent study school. The school district has also invested in going all solar at school sites to cut energy costs. Union City lies within the Ohlone Community College District and Chabot-Las Positas Community College District. As of 2019, the median price of a house in Union City is between $800,000 and $1,000,000.