12 FDIC-insured banks operate 16 branches in Brown County, South Dakota, holding $2.00B in total deposits as of the 2026 FDIC Summary of Deposits. Dacotah Bank leads the market with 43.0% share. Deposit market share is the clearest available measure of competitive position in a local market: it reflects where households and businesses actually keep their money, rather than where institutions advertise or how many branches they operate.
Understanding a deposit market requires knowing the market itself. These figures come from the US Census Bureau American Community Survey 2024 five-year estimates. Median family income is the measure federal regulators use to define low- and moderate-income thresholds under the Community Reinvestment Act, which is why it is reported here separately from household income.
| Population | 37,877 |
|---|---|
| Median family income | $100,857 |
| Median home value | $221,100 |
| Banks operating in county | 12 |
| Bank branches | 16 |
Ranked by deposits held within county borders. A bank's county deposits are the sum across all of its branches in that county, so an institution with several locations appears once. Figures are as of June 30, 2026, the annual reporting date for the FDIC Summary of Deposits.
| Rank | Bank | Deposits | Share | Branches |
|---|---|---|---|---|
| 1 | Dacotah Bank | $861.9M | 43.05% | 3 |
| 2 | Plains Commerce Bank | $285.5M | 14.26% | 1 |
| 3 | Wells Fargo Bank, National Association | $221.3M | 11.05% | 1 |
| 4 | First Interstate Bank | $188.7M | 9.43% | 2 |
| 5 | American Bank & Trust | $120.3M | 6.01% | 1 |
| 6 | BankNorth | $104.6M | 5.22% | 2 |
| 7 | U.S. Bank National Association | $88.2M | 4.41% | 1 |
| 8 | Great Plains Bank | $49.1M | 2.45% | 1 |
| 9 | CorTrust Bank National Association | $37.8M | 1.89% | 1 |
| 10 | The First National Bank of Frederick | $25.5M | 1.27% | 1 |
| 11 | First Savings Bank | $18.8M | 0.94% | 1 |
| 12 | Cornerstone Bank | $385,000 | 0.02% | 1 |
The FDIC Summary of Deposits is an annual survey of branch office deposits filed by every FDIC-insured institution as of June 30 each year. It is the authoritative source for local deposit market share and is the dataset regulators use when assessing competitive effects of bank mergers. Because it is annual, it reflects a point in time rather than current balances. Vault republishes it without modification, free to access and free to cite. Available to AI agents at vaultbot.ai/mcp.