Union County, PA zoning map, flood zone and property lines by address
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Towns in Union County: Lewisburg, Mifflinburg, Linntown.
Flood zone by address
ParcelSheet reads FEMA's National Flood Hazard Layer at the lot: the zone, whether it is a high risk area where lenders ask for flood insurance, and the base flood elevation where FEMA lists one. FEMA's countywide study for Union County has 44 FIRM panels, the newest effective February 2021; no coastal V zones are mapped in it.
The official panel and any Letter of Map Amendment are at FEMA's Map Service Center. An elevation certificate for a Union house comes from a licensed surveyor and is often on file with the county or city building office.
Property lines
The parcel outline, parcel number and mapped size come from the Pennsylvania county parcel layers (each county publishes its own), so a Union lot shows the same lines the county assessment office draws. Union County covers about 202,212 acres of land and 1,140 acres of water.
Mapped lines are approximate. The Union County assessment office keeps the parcel record (Union County website); a licensed surveyor sets the true corners.
Zoning
In Pennsylvania zoning is set by the township, borough or city, or the county where the municipality has no zoning of its own: in Union County, Lewisburg, Mifflinburg each zone the land inside their limits. ParcelSheet shows the use code on the lot's parcel record and the municipality it sits in; the township or borough zoning office has the district, the uses it allows and the lot size it needs. The Union County website lists the county's municipalities.
ADU and guest houses
Under Pennsylvania Municipalities Planning Code (Act 247 of 1968, 53 P.S. 10101 and following), the township, borough or city, or the county where the municipality has no zoning of its own can allow an accessory dwelling unit on a lot with a house. Whether a Union lot can add one depends on its district; the township or borough zoning office has the rule. ParcelSheet shows the mapped lot size and the ground's slope, the first two things the question turns on.
Septic and soil
ParcelSheet reads the USDA soil survey at the lot: the soil's name, its septic absorption rating and whether it is prime farmland. Union County is soil survey area PA119, Union County, Pennsylvania, last updated September 2026, on Web Soil Survey.
A new or changed septic system in Union County needs a permit from the local agency's sewage enforcement officer (the township, borough, joint agency or county health department, under Pennsylvania DEP Act 537 rules).
Setbacks
Setbacks in Union County come from the zoning district: the front, side and rear distances a house must keep. ParcelSheet does not draw setback lines; the township or borough zoning office gives them for the lot's district, and Lewisburg and Mifflinburg for land inside their limits.
Hazards that apply
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near a Union lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in Union County?
Type the address in the box above and ParcelSheet reads FEMA's flood zone at the lot's center. FEMA's countywide flood map for Union County has 44 panels, the newest effective February 2021. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in Union County?
Open the Pennsylvania map, type the address, and the parcel outline from the Union County assessment office shows on the map with its parcel number and mapped size. Mapped lines are approximate; only a licensed surveyor sets the true corners.
What is my property zoned in Union County?
Zoning in Union County is set by the township, borough or city, or the county where the municipality has no zoning of its own (such as Lewisburg, Mifflinburg). ParcelSheet shows the use code on the parcel record and names the municipality; the township or borough zoning office has the final word.
Can I build an ADU in Union County?
Under Pennsylvania Municipalities Planning Code (Act 247 of 1968, 53 P.S. 10101 and following), the township, borough or city, or the county where the municipality has no zoning of its own can allow an accessory dwelling unit, and each sets its own rules. In Union County ask the township or borough zoning office for the lot's district first; ParcelSheet shows the lot size as mapped so you can see the room you have.
Do I need a septic permit in Union County?
Yes. A new or changed septic system in Union County needs a permit from the local agency's sewage enforcement officer (the township, borough, joint agency or county health department, under Pennsylvania DEP Act 537 rules). ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area PA119 (Union County, Pennsylvania).
What can I build on 5 acres in Union County?
Zoning in Union County is set by the township, borough or city, or the county where the municipality has no zoning of its own (such as Lewisburg, Mifflinburg). The zoning district decides the uses, how many homes and the smallest lot it allows on 5 acres. ParcelSheet shows the lot size as mapped and the use code on the parcel record; the township or borough zoning office has the district and its rules. See the Union County website.
What are the residential setbacks in Union County (2026)?
Setbacks in Union County come from the zoning code of the municipality the lot sits in: the front, side and rear distances depend on the lot's district. ParcelSheet does not draw setback lines or give a number it did not read; the township or borough zoning office gives them for the district. See the Union County website.
Next to Union County: Centre County, Clinton County, Lycoming County, Mifflin County, Northumberland County, Snyder County.
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