Hartley is a township in Union County, Pennsylvania, home to about 1,701 people across 80 square miles. Its ZIP codes are 17835, 17845 and 17885, and parts of 17844 are in Hartley too.
Homes sold for a median of $133 per square foot across 3 ZIP codes in the three months ending August 2026, and 1 of 3 were seller’s markets.
All in Hartley
Mostly Hartley; also Lewis Township (Union County) and Hartleton
All in Hartley
Mostly Mifflinburg; part is in Hartley
Each card is that ZIP code’s whole market, including any part outside Hartley. Seller’s market: under 4 months of supply; buyer’s market: over 6. Methodology
We’re writing up Hartley’s story and what everyday life there is like, for people thinking about moving in.
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| Nearest major airport | Philadelphia International Airport (PHL)124 miles away |
|---|---|
| Closer regional airport | Williamsport Regional Airport (IPT)28 miles away |
| Nearest city of 250,000+ | Baltimore, MD114 miles away |
| Nearest city of 1 million+ | Philadelphia, PA124 miles away |
Straight-line distances from the center of Hartley; driving is longer.
Source: Airports from OurAirports (scheduled passenger service); city centers and populations from the U.S. Census Bureau.
Source: Members of Congress from the congress-legislators project; districts from the Census Bureau’s relationship files; governor and mayor from Wikidata.
Hartley had 1,748 residents in the 2020 census, up 2% since 2000.
It’s the 1344th largest of 2,568 towns in Pennsylvania by population.
Union County grew from 17,592 residents in 1900 to 42,681 in 2020.
Union County, 1900–2020
Source: U.S. Census Bureau decennial censuses (counties 1900–1990 from the Bureau’s historical county file).
Average highs peak around 84°F in summer, and winter lows average 15°F. About 42.4 inches of rain and melted snow fall in a typical year, with about 35 inches of snow.
Source: NOAA 1991–2020 climate normals, Millheim, PA weather station (15 miles away).
16,233 jobs at 960 businesses in Union County. The biggest industries by employees:
Source: U.S. Census Bureau County Business Patterns 2023 (private employers; jobs counted where people work).
1 doctors and other health care providers list an office in Hartley’s ZIP codes.
Nearest hospitals
Providers with an office here
| Physical and occupational therapists | 1 |
|---|
Source: Hospitals from CMS Hospital General Information (ratings are CMS overall star ratings); straight-line distances; providers from the CMS National Plan and Provider Enumeration System (NPPES), by practice address and primary specialty.
Parks (2 nearby)
Grocery stores (1 nearby)
Pharmacies
Libraries
Museums
Theaters and performance venues (1 nearby)
Counts are within about 6 miles of the center of town.
Source: Map data © OpenStreetMap contributors (openstreetmap.org/copyright), as mapped by volunteers; it can miss places or include closed ones.
| School | Grades | Students | Affiliation | Distance |
|---|---|---|---|---|
| Millmont Mennonite SchoolMillmont | 1–8 | 43 | Mennonite | 2.3 mi |
Source: U.S. Department of Education, NCES: Common Core of Data for public schools; Private School Universe Survey (2023-2024) for private schools. Listed by address; we don’t rate schools.
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Shares ZIP codes with Mifflinburg, West Buffalo, Limestone Township (Union County), Buffalo Township (Union County), Lewis Township (Union County) and Hartleton.
Town boundaries don’t always match ZIP codes: a ZIP code can cross into neighboring towns, and a town can share a ZIP code with its neighbors. Facts describe the town itself; market figures describe whole ZIP codes.