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Welcome to Saint Clair County ...

Time Zone: Saint Clair County lies in the Central Time Zone (CST/CDT) and observes daylight saving time.

The community of Belleville is the Seat for Saint Clair County.

Saint Clair County is one of the original counties of Illinois and was founded in 1790.

From the Census Estimates for 2019, <1> Saint Clair had a population of 259,686 people. This is a decrease of 3.95% since the last Census (which gave a population of 270,353 people in 2010).

At the time of the 2010 Census, Saint Clair represented 2.11% of the total population of Illinois.

Below are some of the communities located in Saint Clair County:

  • Alorton
    (7 miles [11.3 km] to the northwest)
    • Alorton is located in Saint Clair County (IL)
    • Jump to our Gazetteer entry for Alorton
    • Population from the 2020 Census: 1,880 people
    • Jump to TripAdvisor's Tourism page for Alorton <2>
  • Belleville
    (Less than 2 miles to the southeast)
    • Belleville is located in Saint Clair County (IL)
    • Jump to our Gazetteer entry for Belleville
    • Population from the 2020 Census: 40,536 people
    • Jump to TripAdvisor's Tourism page for Belleville <2>
  • Brooklyn
    (12 miles [19.3 km] to the northwest)
    • Brooklyn is located in Saint Clair County (IL)
    • Jump to our Gazetteer entry for Brooklyn
    • Population from the 2020 Census: 687 people
  • Cahokia
    (10 miles [16.1 km] to the west)
    • Cahokia is located in Saint Clair County (IL)
    • Jump to our Gazetteer entry for Cahokia
    • Population from the 2020 Census: 13,742 people
    • Jump to TripAdvisor's Tourism page for Cahokia <2>
  • Caseyville
    (7 miles [11.3 km] to the north)
    • Caseyville is located in Saint Clair County (IL)
    • Jump to our Gazetteer entry for Caseyville
    • Population from the 2020 Census: 4,115 people
    • Jump to TripAdvisor's Tourism page for Caseyville <2>
  • Centreville
    (6 miles [9.7 km] to the west)
    • Centreville is located in Saint Clair County (IL)
    • Jump to our Gazetteer entry for Centreville
    • Population from the 2020 Census: 4,844 people
  • Dupo
    (11 miles [17.7 km] to the west)
    • Dupo is located in Saint Clair County (IL)
    • Jump to our Gazetteer entry for Dupo
    • Population from the 2020 Census: 3,845 people
    • Jump to TripAdvisor's Tourism page for Dupo <2>
  • East Carondelet
    (13 miles [20.9 km] to the west)
  • Continue List   (19 more) ...
    • East Saint Louis
      (9 miles [14.5 km] to the northwest)
    • Fairmont City
      (9 miles [14.5 km] to the northwest)
      • Fairmont City is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Fairmont City
      • Population from the 2020 Census: 2,439 people
    • Fairview Heights
      (4 miles [6.4 km] to the north)
    • Fayetteville
      (15 miles [24.1 km] to the southeast)
      • Fayetteville is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Fayetteville
      • Population from the 2020 Census: 336 people
    • Freeburg
      (8 miles [12.9 km] to the southeast)
      • Freeburg is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Freeburg
      • Population from the 2020 Census: 4,223 people
      • Jump to TripAdvisor's Tourism page for Freeburg <2>
    • Lebanon
      (11 miles [17.7 km] to the northeast)
      • Lebanon is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Lebanon
      • Population from the 2020 Census: 4,225 people
      • Jump to TripAdvisor's Tourism page for Lebanon <2>
    • Lenzburg
      (19 miles [30.6 km] to the southeast)
      • Lenzburg is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Lenzburg
      • Population from the 2020 Census: 481 people
      • Jump to TripAdvisor's Tourism page for Lenzburg <2>
    • Marissa
      (23 miles [37 km] to the southeast)
      • Marissa is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Marissa
      • Population from the 2020 Census: 1,785 people
      • Jump to TripAdvisor's Tourism page for Marissa <2>
    • Mascoutah
      (11 miles [17.7 km] to the east)
      • Mascoutah is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Mascoutah
      • Population from the 2020 Census: 8,076 people
      • Jump to TripAdvisor's Tourism page for Mascoutah <2>
    • Millstadt
      (6 miles [9.7 km] to the southwest)
      • Millstadt is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Millstadt
      • Population from the 2020 Census: 3,821 people
      • Jump to TripAdvisor's Tourism page for Millstadt <2>
    • New Athens
      (16 miles [25.7 km] to the southeast)
      • New Athens is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for New Athens
      • Population from the 2020 Census: 1,865 people
    • O'Fallon
      (6 miles [9.7 km] to the northeast)
      • O'Fallon is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for O'Fallon
      • Population from the 2020 Census: 29,606 people
      • Jump to TripAdvisor's Tourism page for O'Fallon <2>
    • Saint Libory
      (19 miles [30.6 km] to the southeast)
    • Sauget
      (9 miles [14.5 km] to the northwest)
      • Sauget is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Sauget
      • Population from the 2020 Census: 154 people
      • Jump to TripAdvisor's Tourism page for Sauget <2>
    • Shiloh
      (4 miles [6.4 km] to the east)
      • Shiloh is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Shiloh
      • Population from the 2020 Census: 13,653 people
      • Jump to TripAdvisor's Tourism page for Shiloh <2>
    • Smithton
      (8 miles [12.9 km] to the south)
      • Smithton is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Smithton
      • Population from the 2020 Census: 3,812 people
      • Jump to TripAdvisor's Tourism page for Smithton <2>
    • Summerfield
      (14 miles [22.5 km] to the east)
    • Swansea
      (Less than 2 miles to the northeast)
      • Swansea is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Swansea
      • Population from the 2020 Census: 13,276 people
      • Jump to TripAdvisor's Tourism page for Swansea <2>
    • Washington Park
      (8 miles [12.9 km] to the northwest)
      • Washington Park is located in Saint Clair County (IL)
      • Jump to our Gazetteer entry for Washington Park
      • Population from the 2020 Census: 3,831 people

Websites of Interest ...

Footnotes ...

<1>On a yearly basis, the US Census Bureau creates an estimate of the county's population. Keep in mind that this is an estimate and not an actual count. The last physical count was the 2010 Census and the next count will be for the 2020 Census.
<2>While we're fans and frequent users of TripAdvisor, you should know that we're also members of the TripAdvisor affiliate program.