City comparison
South San Francisco, CA is about 20 miles (30 km) from Union City, CA in a straight line. By road, the drive is roughly 20 miles, or about 25 min behind the wheel at highway speeds.
Driving distance is a rough estimate (great-circle × 1.25); driving time assumes a 60 mph blended average. Real trips run 10–20% longer with stops.
A direct flight from South San Francisco, CA to Union City, CA takes about 2 min, covering roughly 20 miles in a straight line. Connecting itineraries with a layover typically add 1–3 hours.
Block-to-block estimate at ~500 mph cruise, including taxi, climb, and descent — what an airline would publish, not pure airborne time.
Union City has a population of 69,502, vs 65,596 in South San Francisco — about the same size. By land area, Union City covers about 19 sq mi vs 9.2 sq mi for South San Francisco.
Population from US Census ACS. Land area from the Census Gazetteer (city proper, excluding inland water).
Cost indices by category, with the US city average (100) marked.
Index: 100 = US city average. Lower is more affordable.
Side-by-side costs, salaries, and sub-category indices.
| Metric | South San Francisco | Union City | Difference |
|---|---|---|---|
| Median rent | $2,649/mo | $2,593/mo | 2.2% higher in South San Francisco |
| Median home value | $1,113,000 | $1,006,600 | 10.6% higher in South San Francisco |
| Median household income | $127,062 | $138,013 | 8.6% higher in Union City |
| Groceries index | 108.1 | 108.1 | ≈ equal |
| Utilities index | 168.3 | 168.3 | ≈ equal |
| Transportation index | 106.1 | 106.1 | ≈ equal |
| Healthcare index | 106.0 | 106.0 | ≈ equal |
How much you'd need to earn in the other city to keep the same standard of living.
If you earn $100,000 in South San Francisco, you'd need $99,887 in Union City to maintain your standard of living.
Climate, safety, and demographics side by side.
South San Francisco and Union City have nearly identical overall cost-of-living indices. If you earn $80,000 in South San Francisco, you'd need about $79,909 in Union City to keep the same standard of living.