The commercial section, limited to Lancaster Avenue and portions of the adjacent roads, consists of a few individual shops, filling stations, and the printing shop of Charles J. McDevitt, who continues the one-man firm established by his father in the early 1900s. The Rosemont Mall, with twenty shops, was built in 1975 on land where a siding from the railroad used to serve the Mehl and Latta Coal and Lumber yards. Of the two early carriage works, the Derham Body Company continued until 1970.

North of the railroad are fine homes on large plots. Rosemont's stately houses on Montgomery Avenue date from 1868 and 1869, when the Pennsylvania Railroad was straightening and leveling its tracks between Haverford and Rosemont. The railroad had to buy almost three hundred acres of farmland, using part for its tracks and dividing the rest into lots. Those on Montgomery Avenue were priced at $8,000 and on the other streets at $5,000. Building was strictly controlled, as it was in Bryn Mawr.

Apartment houses have now been permitted on Montgomery Avenue. A seven-story condominium containing sixty-seven units, was completed in 1975.

Rosemont's name is derived from Rosemont Farm, the land of Rees Thomas, who reached America in 1683 on the second boat of Welsh people to settle here. He purchased 625 acres lying on Roberts Road extending west between Old Gulph Road and the Delaware County line. In 1785 the southern portion was sold to John Curwen, who, with his four succeeding generations, called their home Walnut Hill. Ashbridge House was built in 1769 on the northern section by one of Rees Thomas's sons, William, and his grandson, Rees Thomas III. Peter Pechin purchased this property in 1850. He left a farm to each of his four children, giving the Rosemont property to Rebecca Emily Pechin Ashbridge. Her husband, Joshua Ashbridge, already owned forty adjoining acres on the south, and the tracts took on their master's name Ashbridge.

A small section of the Ashbridge land was deeded to the Pennsylvania Railroad for a station with the understanding that it be named Rosemont. Both Montgomery Avenue and Airdale Road were constructed through the property, which had a long straight lane to Roberts Road.

Rebecca and Joshua Ashbridge's three daughters inherited the tract in 1891 and, with foresight, planned wills as early as 1906, when Mary died. With the death of the third sister in 1940 the farm was left to Lower Merion Township to be used for recreation. The sisters ran a dairy on the property, selling milk commercially until the Board of Health instituted milk control in 1922, and the Ashbridges could not meet its stringent standards. An old building east of Ithan Avenue, used earlier as a boardinghouse for men working on nearby farms, has been replaced by a modern house. The stable-carriage house and the barn are now used for repairing and storing the township's equipment.

Now named Ashbridge Memorial Park in memory of the soldiers of World War I, the "Tribute Walk" was built by the Rosemont-Villanova Civic Association to honor those who fought in World War II. The area of rare specimen trees, some ancient and some carefully selected by the late Jack Kenealy, tree warden of Lower Merion Township, has been called the "Kenealy Arboretum".

Ashbridge House now contains the library and museum of the Lower Merion Historical Society and is a meeting place for many township groups, while the 28.81 acres provide areas for walking, sledding, jogging, tennis, and a play lot.

The civic association participates in a Community Watch program in conjunction with the police department. Rosemont neighbors worked together a century ago when severe property damage and poverty followed the railroad strike. A "Relief Association" and soup kitchen were initiated by a Rosemont resident, John B. Garrett. In 1888 this organization joined the "Protective Association" organized by John Converse, another outstanding Rosemont citizen. The two groups became known as 53 the Bryn Mawr Citizens' Association. This organization hired its own police to protect private property and the families in 1881, almost twenty years before Lower Merion had its own police department. In the 1930s private citizens again united to form the Mount Moro Protective Association to prevent the dumping of trash and hunting on private property.

One of the finest estates in Rosemont was Rathalla, a spectacular thirty-two-room medieval chateau designed for Joseph Francis Sinnott, a Philadelphia distiller. Rathalla, completed in 1891, is now the centerpiece of the Rosemont College Campus. Two neighboring mansions are used for the school and convent of the Sisters of the Holy Child Jesus.