Flood Zones and Missouri River Flood Risk in Fremont County, Iowa

2011: a complete levee failure at Hamburg

In June 2011, a levee south of Hamburg -- a town of about 1,100 people along the Iowa/Missouri border in Fremont County -- suffered a partial collapse on June 4, followed by further partial failures, and then a total collapse on June 13 when a 300-foot section gave way. Roughly a fifth of Hamburg's population had to evacuate. That summer's Missouri River flooding, driven by heavy upstream snowmelt and rainfall managed through the Missouri River reservoir system, caused five deaths and flooded more than 4,000 homes across the broader region.

2019: a flood that broke the 2011 record by nearly two feet

The 2019 Missouri River flood was worse. In Fremont County specifically, the river crested almost two feet above the previous record set in 2011 -- meaning the 2011 disaster, severe as it was, was not the county's ceiling. Regionally, the 2019 flood breached or overtopped 17 levees along the Missouri River across Iowa, Nebraska, and Missouri, caused crop damage estimated at more than $2 billion, and affected more than 460 businesses. Areas that had never flooded before were inundated in 2019, which matters for evaluating any Fremont County parcel: a location's flood history through 2011 alone is not a reliable guide to its exposure, since 2019 redrew that map.

The county's active response: the Crossroads Levee District and Mule Slough repairs

Fremont County has not treated either flood as a closed chapter. Following a resident petition citing the 2011 and 2019 floods, the county and the Iowa Department of Transportation created the Iowa Highway 2/Interstate 29 'Crossroads' Levee District, with IDOT funding and building the levee to protect businesses at that interchange -- a corridor that sits at the junction of the county's main highway and interstate access. County supervisors' meeting records from April 2026 show an active payment application for that construction, meaning the project was still underway as of that date rather than finished.

Separately, the Mule Slough Drainage District -- infrastructure damaged by the 2019 flood -- was still being repaired six years later: U.S. Representative Randy Feenstra's office announced securing nearly $1.2 million in federal funding for those repairs in 2025. The gap between the 2019 flood and 2025 funding for basic drainage-district repair is itself informative: it shows how long flood-damage remediation can take to fully fund and complete in a rural Iowa county, and that a drainage district's infrastructure being 'not yet fully repaired' years after a flood is a real, current condition here rather than a one-off delay.

What to verify before buying a Fremont County parcel

• A specific parcel's FEMA flood zone designation and any post-2019 remapping, through the Iowa Flood Center's Missouri River Flood Information System (MRFIS) and FEMA's flood maps -- 2019 inundated areas that had not previously been mapped as flood-prone.
• Whether a parcel sits within or depends on the Highway 2/I-29 Crossroads Levee District's protected area, and that project's current completion status, directly with the Fremont County Engineer's office.
• Whether a parcel sits within the Mule Slough Drainage District or another county drainage district, and that district's current infrastructure condition and any pending assessment for repairs, with the county's Drainage District Officials.
• Flood insurance availability and cost for a specific parcel, which can be materially affected by proximity to the Missouri River, levee protection status, and any recent remapping.
• Whether the parcel or any structure on it sustained damage in 2011 or 2019, and whether any required elevation, floodproofing, or buyout condition attached to the property as a result.