Regional Statistics
Population in Sejneński County 2020
In 2020, Sejneński county ranked 380 of 380 Polish counties. Population shrank by 1,340 residents -6.5% between 2015-2020, at 19,266.
Among 339 declining counties, in the bottom 20% for rate of decline. Within Podlaskie voivodeship, ranked 17 of 17 counties.
Based on 31 years of official GUS statistics for Sejneński county and its 5 municipalities within Podlaskie voivodeship.
Popular Cities in Poland
You may also be interested in
Contact Information for Sejneński
Updated 52 days ago
Top tools
Polish IBAN Generator
Generate a valid Polish IBAN from a bank code and account number. See the 28-character PL IBAN format with a real example.
Which Bank Is This IBAN?
Paste any IBAN to identify the bank, branch, and BIC/SWIFT code.
NIP Checker
Verify any Polish NIP (VAT/tax ID) number with an instant checksum check and tax office prefix decode.
Top articles
How to Pay Tax After Buying a Car in Poland
Step-by-step guide to paying PCC tax after buying a used car in Poland. Covers the 2% rate, 14-day deadline, PCC-3 form, and online payment.
9 min readWhich Taxes Are Paid Through a Mikrorachunek in Poland?
PIT, CIT, and VAT go through your mikrorachunek. PCC, property tax, and local fees do not. Here is the full breakdown for taxpayers in Poland.
7 min readHow to Get Polish Citizenship by Descent
How to get Polish citizenship by descent. Eligibility rules, required documents, application steps, costs, and timelines for ancestry-based claims.
10 min readLet's build Poland.gg together
Join our Discord community. Get early access, shape the roadmap, and connect with data people across Poland.
Dashboard and business tools go public in 2027 — early supporters access them first and keep their discount on everything.
Get up to 90% off — forever
The longer you stay, the less you pay. 9% off per month, stacking up to 90%. The 100 longest supporters get free access for life.
© 2026 Poland.gg