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Single Family ResidenceResidential
$240,931$145 / ft²
TopHap EstimateOur estimate of what this home would sell for today, based on nearby sales, the home's size and features, and local price trends. It is a starting point, not an appraisal.· confidence 81How well the pricing models agreed with each other on this home. Higher means the estimate rests on stronger, more consistent data.· as of Sep 24, 2026

4257 420TH ST

ALTON, IA 51003
2.5
Baths
1,657 ft²
Living AreaTotal finished area of the structures, from county records. Some counties include shared space like hallways or a building gym, so it may not match a listing.
4.64 ac
Lot SizeThe size of the land the home sits on, from county records.
2013
Year BuiltThe year the home was originally built, according to county records.
1
StoriesHow many floors the home has above ground.
5
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.
4
ParkingThe number of parking spaces on the property, including the garage.

Valuation

$241K
$194K low$287K high

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$3,800 (2025)
Assessed ValueThe value the county assigns to this home to calculate property tax. It is often lower than what the home would sell for.$443,270 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$48,200
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$395,070
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$370,940
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$443,270

Climate Risk

Projected Flood DepthHow deep a serious flood is expected to get here at some point in the next 30 years. Shown in inches.12 in
30-Year Flood ChanceThe chance of at least one serious flood here in the next 30 years, not in any single year.30%

Scores 0–100; higher = greater projected risk.

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Single Family Residence
CountySIOUX
Lot (acres)The size of the land the home sits on, from county records.4.64
ConstructionThe main material the home's frame and walls are built from.Frame (Unspecified)
RoofThe main material covering the roof, such as asphalt shingle or tile.Asphalt
HeatingThe type of heating system in the home.Yes
CoolingThe type of cooling or air conditioning in the home.Yes
GarageWhether the property has a garage, and details like whether it is attached to the home.Mixed
PoolWhether the property has a pool, and what kind, such as in-ground.No
FeaturesExtra features found in county records. Records are not complete everywhere, so a missing feature does not always mean the home lacks it.Deck · 288 ft²Porch · 92 ft²

Assigned SchoolsThe public schools this address is zoned for. Boundaries change, so confirm with the district before you count on it.

M
Moc-Floyd Valley Middle SchoolA+
Middle · Grades 6–8 · 4.8 mi
E
Moc-Floyd Valley Elementary SchoolA+
Elementary · Grades PK–5 · 5.6 mi
H
Moc-Floyd Valley High SchoolA
High · Grades 9–12 · 6.0 mi

District: Moc-Floyd Valley Community School District

Neighborhood · ZIP 51003These are comparison scores, not percentages. 100 equals the national average, so 150 means about 50% above average.

CrimeLocal crime compared with the rest of the country, where 100 is average. It reflects things like population density, income, and how crime gets reported.117
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.84
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.18

Index scale: 100 = US average (tick). Lower is better.

Homes occupiedThe share of homes here that someone lives in. The rest sit empty, including vacation and for-sale homes.94%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.17%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.4.2%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.0.8%
PopulationHow many people live in this area.2,164
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.39 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$88,017
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$109,952
Average tempThe average temperature here across a full year.46°F
Annual precipHow much rain and melted snow falls here in a typical year.28 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.61%

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Data by ATTOM. Valuations are automated estimates, not appraisals. Photos from Google Street View and may not depict the current property state.

How this home compares

4257 420th St measured against every home in its neighborhood, its ZIP code and its county, using county assessor records refreshed nightly. A home can stand out in one of those areas and look ordinary in another, because each one holds a different mix of homes.

  • Costs less per square foot than 70% of homes in Sioux County
  • Has a bigger lot than 86% of homes in Sioux County
  • Newer than 90% of homes in Alton 51003

What homes are worth in Alton 51003

Each bar is how many homes fall in that price range. The marker is this home.

This home
$71K$633K

This home is worth more than 46% of homes in Alton 51003.

How it measures up in Alton 51003

The dot is this home. The mark in the middle is the typical home in Alton 51003.

Estimated value$240,931
CheaperTypical $259,471Pricier

Pricier than 46% of homes nearby

Price per ft²$145
CheaperTypical $168Pricier

Pricier than 39% of homes nearby

Living area1,657 ft²
SmallerTypical 1,632 ft²Bigger

Bigger than 53% of homes nearby

Lot size4.64 ac
SmallerTypical 0.4 acBigger

Bigger than 84% of homes nearby

Year built2013
OlderTypical 1958Newer

Newer than 90% of homes nearby

How 4257 420th St ranks against every home in each area.
MeasureThis homeAlton 51003Sioux County
Estimated valuepricier than$240,93146% of homes39% of homes
Price per ft²pricier than$14539% of homes30% of homes
Living areabigger than1,657 ft²53% of homes62% of homes
Lot sizebigger than4.64 ac84% of homes86% of homes
Year builtnewer than201390% of homes90% of homes

About 4257 420th St

How much is 4257 420th St, Alton, IA worth?

The TopHap Estimate for 4257 420th St, Alton, IA is $240,931 as of Sep 24, 2026. The likely range is $194,370 to $287,492. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 4257 420th St, Alton, IA last sell?

4257 420th St, Alton, IA last sold on Jan 1, 1900, according to the county's recorded deed.

How big is 4257 420th St, Alton, IA?

4257 420th St, Alton, IA has 2.5 bathrooms, 1,657 square feet of living space and a 4.64-acre lot.

When was 4257 420th St, Alton, IA built?

4257 420th St, Alton, IA was built in 2013, making it 13 years old. The building has 1 story.

What schools serve 4257 420th St, Alton, IA?

4257 420th St, Alton, IA is assigned to Moc-Floyd Valley Middle School (middle), rated A+; Moc-Floyd Valley Elementary School (elementary), rated A+; Moc-Floyd Valley High School (high), rated A. All sit in Moc-Floyd Valley Community School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 4257 420th St, Alton, IA compare to other homes in Alton 51003?

Among the 670 homes in Alton 51003, it is worth more than 46% of them ($240,931 against a typical $259,471), its price per square foot is higher than 39% of them ($145 against a typical $168), it is bigger than 53% of them (1,657 ft² against a typical 1,632 ft²), its lot is bigger than 84% of them (4.64 ac against a typical 0.4 ac) and it is newer than 90% of them (2013 against a typical 1958). Measured against all of Sioux County, it is worth more than 39% of homes there. These shares are recounted nightly from the full county assessor record for each area, not from active listings.

What are the property taxes on 4257 420th St, Alton, IA?

The 2025 property tax bill for 4257 420th St, Alton, IA was $3,800. The county assessed it at $443,270.

More homes on 420th St

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