Hazel Dell is an unincorporated area and census-designated place (CDP) in Clark County, Washington, United States, located north and west of Vancouver. As of the 2020 census, Hazel Dell had a population of 23,569. Previous censuses divided the community into two areas, Hazel Dell North and Hazel Dell South.

Oregon Country pioneers Reese and Sarah J. Anderson were Hazel Dell's first settlers. Sarah named the area after a stand of filberts on their land near 78th Street and Highway 99. She also donated the land for the first school in Hazel Dell, the present site of Hazel Dell Elementary School. The name "Bear Gulch" was briefly considered by the early Hazel Dell residents. Local business leaders once considered changing the name to "Basilville" in honor of enterprising merchant Basil Dhanens. With thanks, Dhanens declined the offer. He died in 1972.

Hazel Dell and Minnehaha were two of the first suburban areas to be developed after World War II and were followed by Lake Shore, Felida, and Salmon Creek. Much of the housing boom in the area has subsided due to the increase of homes being built to the east of Vancouver, between Interstate 205 and Camas and Washington State Route 500/Fourth Plain Boulevard and the Columbia River.^{[citation needed]}

Hazel dell was historically an agricultural community and until the early 1970s, it was not uncommon to see horses and dairy cattle at several points along Interstate 5 and Highway 99 in Hazel Dell. Dairy production largely has ceased in the area yet some smaller acreage farms persist. The Clark County 78th Street Heritage Farm is also in Hazel Dell. The Heritage Farm was the county poor farm from the late 1800s until the late 1940s, and Washington State University's Vancouver Research and Extension Unit until 2008, when it was returned to County management as a public agricultural resource used by multiple farm partners including the Clark County Food Bank, WSU Clark County Extension, and Master Gardener Foundation of Clark County. Hazel Dell is increasingly residential and commercial, with multiple shopping centers.^{[citation needed]}

Hazel Dell runs parallel to and is bisected by Interstate 5, with access from exits 4 and 5. The community is bounded by the Vancouver city limits on the south in the vicinity of Burnt Bridge Creek, Lake Shore to the west, Salmon Creek to the north, I-205/Barberton to the northeast, and Walnut Grove to the east. Vancouver Lake is a short distance to the west of the area, and the community of Minnehaha is to the southeast. According to the United States Census Bureau, the Hazel Dell CDP has a total area of 4.9 square miles (12.6 km²), of which 0.01 square miles (0.03 km²), or 0.27%, is water.

Hazel Dell first appeared as a census designated place in the 2010 U.S. census formed out of the deleted Hazel Dell North and Hazel Dell South CDPs.

As of the 2020 census, Hazel Dell had a population of 23,569. The median age was 36.7 years. 21.8% of residents were under the age of 18 and 15.7% of residents were 65 years of age or older. For every 100 females there were 97.1 males, and for every 100 females age 18 and over there were 95.2 males age 18 and over.

100.0% of residents lived in urban areas, while 0.0% lived in rural areas.