Floodplain Program

Since the 1980s, Lewis and Clark County has assisted County residents with recovering from flood events by voluntarily participating in the National Flood Insurance Program (NFIP). Participation in the program provides County residents with disaster assistance when a Presidential Disaster Declaration is made. The County has a peak flood season from May to June, which are usually the wettest months of the year. Major flood events hit the County in 1975, 1981, 1996, 2011, and 2018.

Lewis and Clark County adopted the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Maps (FIRMs) on September 19, 2012. The County regulates to over 30 maps that include various rivers and creeks from the Helena Valley, York, Craig, Augusta, and Lincoln. These maps are available at the CDP or viewable online.

Lewis and Clark County adopted its most recent Floodplain Ordinance in November 2022. The County Floodplain Ordinance regulates the identified floodplains. A floodplain permit is required before developing in the floodplain, which includes, but is not limited to, residential and nonresidential development, bridge construction, culvert installation, drilling, and excavation. Please contact the CDP for a permit application.

Floodplain Ordinance(PDF, 421KB)