Big Sioux Township, Union County, South Dakota
Big Sioux Township is a township in Union County, South Dakota. About 4,917 people live there (2020–2024 estimate). It covers 10.8 sq mi (28.1 km²) of land and uses Central Time. It has its own local government.
- Population, 2020–2024 estimate
- 4,917 ± 20
- County
- Union County
- School district
- Dakota Valley School District 61-8
- Land area
- 10.8 sq mi (28.1 km²)
- Type
- TownshipIts own local government
- Time zone
- Central TimeUTC-06:00 in January; UTC-05:00 in July
- Median household income
- $128,005 ± $20,937
- Median home value
- $502,200 ± $65,876
- Water area
- 1.34 sq mi (3.48 km²)
- State
- South Dakota
- Census code (GEOID)
- 4612705380
- Coordinates (central point)
- 42.523328, -96.509711
These coordinates mark a central point for the area, not a street address. Population, income and home value: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, ± margin at 90% confidence; checked on October 20, 2026.
Census place in Big Sioux Township
- Dakota Dunes (CDP)3,936 people
This place’s central point lies inside Big Sioux Township. A place can reach across the line, and its government, if it has one, can be separate from the township’s.
Bordering areas, nearest first
- North Sioux City (city)1.2 mi northeast
- Covington Precinct, Dakota County, Nebraska3.6 mi south
- Jefferson Township4.8 mi northwest
- Sioux City, Iowa (city)6.4 mi east
- St. Johns Precinct, Dakota County, Nebraska7.4 mi southwest
These towns, townships, cities and boroughs share a boundary with Big Sioux Township. Distances are straight lines between central points, not driving distances.
Other townships in Union County, largest first
- Jefferson Township1,088 people
- Virginia Township315 people
- Spink Township270 people
- Brule Township254 people
- Big Springs Township237 people
- Civil Bend Township191 people
- Prairie Township155 people
- Alcester Township142 people
- Emmet Township140 people
- Sioux Valley Township112 people
- Elk Point Township91 people
People counts are American Community Survey 2020–2024 5-year estimates. See Union County for its cities, ZIP Code areas and county seat.
Sunrise and sunset in Big Sioux Township
- Longest day
- 15 hours 19 minutes around June 21
- Shortest day
- 9 hours 3 minutes around December 21
- Earliest sunrise
- 5:48 AM around June 15
- Latest sunrise
- 8:05 AM the day before clocks go back in November
- Earliest sunset
- 4:52 PM around December 9
- Latest sunset
- 9:07 PM around June 27
Clocks go forward an hour on the second Sunday in March and back on the first Sunday in November, so sunrise and sunset jump an hour later in March and an hour earlier in November.
| Day | Sunrise | Sunset | Daylight |
|---|---|---|---|
| Jan 15 | 7:53 AM | 5:18 PM | 9 h 25 min |
| Feb 15 | 7:22 AM | 5:57 PM | 10 h 35 min |
| Mar 15 | 7:38 AM | 7:32 PM | 11 h 54 min |
| Apr 15 | 6:45 AM | 8:07 PM | 13 h 22 min |
| May 15 | 6:04 AM | 8:41 PM | 14 h 37 min |
| Jun 15 | 5:48 AM | 9:05 PM | 15 h 17 min |
| Jul 15 | 6:02 AM | 9:01 PM | 14 h 59 min |
| Aug 15 | 6:32 AM | 8:27 PM | 13 h 55 min |
| Sep 15 | 7:05 AM | 7:35 PM | 12 h 30 min |
| Oct 15 | 7:38 AM | 6:44 PM | 11 h 6 min |
| Nov 15 | 7:17 AM | 5:03 PM | 9 h 46 min |
| Dec 15 | 7:48 AM | 4:53 PM | 9 h 5 min |
Approximate times for a flat horizon at the central point; the days move by a day or so from year to year. Hills and weather can change what you see.
Before using this answer on a form
A township line is not always the line on your mail: a mailing address can name another town or post office, and school districts, ZIP Codes and tax districts follow their own lines. For taxes, voting or permits, check the full address with Union County or the local office.
Find the township or town where you are now or find your county.