Documented founding year
Inferred: IRS exemption ruling year
Undated (shown when toggled)
(pin appears in the year the office began; hover for details)
(documented, sourced actions only)
IRS ruling years record when an organization received tax exemption. They are not founding years and are often later. Points are research data with known gaps; see the methodology.
1920
Officeholder pins use the person’s first-known start date; 220 listed people have no known start date and are not shown. Pins sit at the city or county seat, or at the state capital when only a state office is known.
Calibration (survey estimates, not in dataset): dashed markers in chart.