Upper Stewartsville is an unincorporated census-designated place within Greenwich Township, Warren County, situated at an elevation of 417 feet in the rolling hills of northwestern New Jersey — a landscape shaped by the Kittatinny Ridge to the north and the Delaware River valley to the west. With a population of just 329 residents spread across a compact footprint, this is one of Warren County's most intimate communities, offering a pace of life that stands in sharp contrast to the busier corridors of nearby Phillipsburg or the commercial sprawl along Route 22.

What distinguishes Upper Stewartsville is its genuine small-town character within a township that retains significant open space and agricultural heritage. Residents fall under the Greenwich Township school system, and the community benefits from reasonable access to Interstate 78, making it a practical option for commuters traveling toward the Lehigh Valley in Pennsylvania or points east into New Jersey's suburban counties. The population grew by more than 55 percent between 2010 and 2020, signaling quiet but real momentum.

For buyers seeking affordability, privacy, and a strong sense of place without sacrificing regional connectivity, Upper Stewartsville represents exactly the kind of Warren County address that rewards those willing to look beyond the obvious.

Tucked into Warren County along the rolling hills of western New Jersey, this small enclave of just 128 residents offers a community profile that is genuinely extraordinary. With a median household income of $250,001 — more than three times the national median of roughly $75,000 — and 52.9% of households earning six figures, Upper Stewartsville represents a concentration of quiet, established prosperity that is rare at any scale. Perhaps most striking of all: the community carries a poverty rate of 0% and an uninsured rate of 0%, meaning every household here enjoys a meaningful degree of financial security and health coverage.

The educational profile is equally impressive. 83.2% of residents hold a bachelor's degree or higher — more than double the national average — and nearly half, 49.5%, have earned a graduate degree. A remarkable 72.2% hold STEM credentials, suggesting a community shaped by technical and professional careers. The median age of 56.2 years and a labor force participation rate of 51.6% point to a neighborhood of accomplished professionals who have reached or are approaching retirement, enjoying the fruits of long careers. With a homeownership rate of 100% across all 34 housing units and an average family size of 3.76, this is a place where people put down deep roots — and stay.

Outdoor Recreation

Upper Stewartsville sits at an elevation of over 400 feet in the rolling hills of Warren County, placing it squarely in some of New Jersey's most scenic countryside. The surrounding Greenwich Township landscape is laced with open farmland, wooded ridges, and quiet country roads that invite hiking, cycling, and nature walks. Merrill Creek Reservoir, located just a short drive away, offers excellent fishing, birdwatching, and trail hiking along its 15-mile perimeter path — a genuine gem for outdoor enthusiasts in this corner of the state. The Delaware Water Gap National Recreation Area is also within easy reach, offering world-class hiking, paddling, and swimming along the Delaware River.

Parks & Family Activities

Warren County's extensive park system provides residents of Upper Stewartsville with accessible green space and recreational amenities nearby. Merrill Creek Reservoir Environmental Preserve doubles as a family-friendly destination with educational programming about the local watershed and wildlife. The broader region is well-suited for families who enjoy apple picking and farm visits in the fall, as Warren County's agricultural heritage means working farms and seasonal farm stands are part of everyday life here.

Dining & Local Flavor

Upper Stewartsville itself is a small, tight-knit community, so residents typically head to nearby Stewartsville or the larger towns of Washington and Phillipsburg for dining and shopping. Phillipsburg, just a few miles to the north along the Delaware River, offers a revitalized downtown with local eateries, antique shops, and a growing arts scene. Washington Borough, the Warren County seat, provides additional dining options, grocery stores, and everyday conveniences.

Arts, Culture & Day Trips

The region's history runs deep — Warren County was a hub of early American industry, and nearby historic sites reflect that heritage. The Delaware River corridor offers scenic drives and access to charming river towns on both the New Jersey and Pennsylvania sides. For broader cultural outings, residents are roughly 60 miles from both New York City and Philadelphia, making Upper Stewartsville a surprisingly well-positioned base for enjoying world-class museums, theater, and entertainment while returning home to genuine small-town tranquility.

A Small Community with Deep Warren County Roots

Upper Stewartsville sits within Greenwich Township in Warren County, New Jersey, a region shaped by centuries of agricultural settlement along the fertile lands of the Musconetcong and Delaware River valleys. The broader Stewartsville area — of which this community is the northern counterpart — developed as part of Warren County's 19th-century rural landscape, when small hamlets clustered along roads and ridgelines served the farming families and tradespeople of the surrounding township.

Greenwich Township itself was formed in 1798, and the surrounding area grew steadily through the 1800s as Warren County became known for its iron industry, limestone quarrying, and productive farmland. Upper Stewartsville's elevated position — sitting at roughly 417 feet above sea level — reflects the rolling topography characteristic of this part of northwestern New Jersey, where the Kittatinny Ridge and the Warren County highlands define the landscape.

Notably, Upper Stewartsville did not appear as a formal census-designated place until the 2010 U.S. Census, when it was among a wave of newly defined CDPs across Warren County. At that time, the community counted just 212 residents. By 2020, that number had grown to 329 — a 55 percent increase that signals quiet but meaningful residential interest in this corner of Greenwich Township.

That growth pattern is directly relevant to today's real estate picture. Upper Stewartsville remains a genuinely small community — just 0.35 square miles — where housing inventory is limited and turnover is infrequent. Its median age of 40.1 reflects an established, family-oriented population, and the demographic diversification recorded between 2010 and 2020 suggests a community gradually opening to new residents drawn by Warren County's affordability and rural character.

Four Distinct Seasons in Warren County's Highlands

Upper Stewartsville experiences a humid continental climate, characteristic of inland New Jersey at elevated terrain. Sitting at roughly 417 feet above sea level in Warren County, the community sits well removed from any moderating coastal influence, meaning residents experience the full range of seasonal extremes that define this climate type.

Summers are warm and humid, with daytime highs typically reaching the mid- to upper 80s°F and overnight lows settling in the low 60s. Winters are cold and occasionally harsh, with average highs in the mid-30s°F and lows that frequently dip into the teens and 20s. Snowfall is a reliable seasonal feature, with the surrounding Warren County hills capable of enhancing accumulations compared to lower-lying areas of the state.

Precipitation is fairly well distributed throughout the year, averaging around 45–50 inches annually, with no pronounced dry season. Spring and summer thunderstorms are common, and nor'easters can bring significant snow or ice during winter months. The elevation and inland position mean temperature swings between seasons are pronounced.

For prospective homeowners, these patterns carry real practical implications. Heating costs are a meaningful budget consideration given the length and intensity of winter. Air conditioning is a summer necessity. Homes should be evaluated for insulation quality, roof condition, and drainage — all of which face regular seasonal stress in this climate.

The Upper Stewartsville real estate market is showing a steady increase in home values, with a 3.8% rise over the past year, reaching an average of $511,901, which is a positive sign for sellers. At Opulist, we interpret this trend as a sign of a stable market, where buyers and sellers can negotiate fairly. With 23 homes currently for sale and 13 new listings, the market is experiencing moderate activity, suggesting that now may be a good time to buy or sell a home in Upper Stewartsville.

Upper Stewartsville Home Value Index over time.