The city lies at the eastern end of the Snohomish River floodplain, with elevations that range from . The south and east edges of the city along the Skykomish River are within a 100-year flood hazard zone and also include habitats for migratory birds and game animals. The residential neighborhoods of Monroe lie within the watersheds of French Creek and Woods Creek, which both drain into the Skykomish River before its confluence with the Snoqualmie and Snohomish rivers. The surrounding area includes hills and plateaus that were formed from glacial till and gravel deposits from the Skykomish River. Monroe also sits on a local fault line that produced a pair of minor earthquakes on July 12, 2019, that were felt as far as Seattle and Vancouver without causing damage.
the city lies at the eastern end of the snohomish river floodplain with elevations that range from  the south and east edges of the city along the skykomish river are within a 100-year flood hazard zone and also include habitats for migratory birds and game animals the residential neighborhoods of monroe lie within the watersheds of french creek and woods creek which both drain into the skykomish river before its confluence with the snoqualmie and snohomish rivers the surrounding area includes hills and plateaus that were formed from glacial till and gravel deposits from the skykomish river monroe also sits on a local fault line that produced a pair of minor earthquakes on july 12 2019 that were felt as far as seattle and vancouver without causing damage