Ellwood City, a borough in southern Lawrence County, became a Beaver County community in 1918 when a strip of North Sewickley township was annexed. Henry W. Hartman founded Ellwood City in 1889, naming it after his friend and fellow industrialist, Isaac L. Ellwood of Illinois. Intended from the beginning as an industrial center, a variety of industries were attracted to the new community as soon as the first lots were sold. In 1892, the same year that the borough was incorporated, the Ellwood Shafting and Tube Company started production. This was the beginning of what would become the towns largest industry, (after several name changes) the Ellwood Works of the United States Steel Corporation.
Hazel Dell, a neighboring community to the north across Connoquenessing Creek, was incorporated in 1901. The two borough consolidated in 1914, and Hazel Dell became Ellwood City's fourth ward.
As early as 1894, a plan of lots was laid out south of town and across the county line followed Division Avenue for much of its course through town. South Ellwood, as it was called, was expanded by additional plans until, in 1918, the entire area was annexed to the borough as part of the Second Ward. Many of the Italian immigrant families who arrived in Ellwood in the early part of the twentieth century settled in this section. Alexander Gardener and E. G. Matthey were early landowners in this area.
The hilly Beaver County section of Ellwood City is little changed in 1976, except for the new limited access highway leading south to a new bridge constructed over the Connequenessing.