Upon arriving in Princeton, McCosh delivered his first speech on the steps of the President's House and immediately endeared himself to the student body by expressing his support for organized athletics. This idea was less popular with some of the conservative Trustees, who frowned on athletics as unduly secular. But McCosh believed that a good education nourished the body as well as the mind, and the first structure built under the McCosh administration was a gymnasium.

Sports at the College of New Jersey to that point had been haphazard at best, with students taking the initiative in most cases. The first gym, little more than a wooden shack, had to be burned down in 1865 after a tramp suspected of carrying smallpox slept there. Despite increasing agitation from the students during the next several years, it was not replaced.

In November 1868, at McCosh's urging, the Trustees commissioned a new gymnasium. The cost of $38,000 was split between two donors, Robert Bonner and Henry G. Marquand, and the building was named in their honor. It was only the second building on the campus to be named for the donor. (Halsted Observatory was the first.) Constructed during 1869, it was dedicated on January 13, 1870.

George B. Post designed the new gym. It was 90 feet long and 45 feet wide, roughly the size of a modern basketball court, and was located on the west side of the campus, between Halsted Observatory and West College. Made of gray stone with a slate roof, it featured twin octagonal towers on each end of the building.

Stylistically, Bonner-Marquand represents a transition from classical models to the more ornate High Victorian Gothic structures that would soon flood the campus. It contains some hints of what was to come: turrets, for instance, would reappear in several buildings and each floor featured a different window style. But at the same time, Bonner-Marquand does not fall in the full-blown high Victorian Gothic style typified at Princeton in the buildings of William Potter (such as the Chancellor Green Library).

Inside, the gymnasium was a marvel. The College hired the Scot George Goldie --described as "the eminent gymnast of New York City" -- as its first instructor in physical education. This appointment led some to joke of the danger of having Scotsmen in charge of both the mental and physical development of the students. Gymnastics was the most popular sport of the period, and Goldie outfitted the high-ceilinged second floor of the gym with gymnastic apparatus, climbing ropes, and weights.

The shorter ground floor, meanwhile, was occupied by six bowling alleys. In 1875, one of the bowling alleys was removed and replaced with four billiards tables, donated by Percy Pyne. The basement of gym contained the College's first bathtubs and outside stood a sculpture of a gladiator.

When it was completed, Bonner-Marquand Gymnasium (Architecture Catalog Entry) was considered the most sophisticated college gymnasium in the U.S. But the College grew rapidly and students began to complain about the limited space and facilities in the building. In 1895, the Daily Princetonian even described the gym as a "disgrace to the institution." A new gymnasium, paid by general alumni subscriptions, was built in 1903. Bonner-Marquand Gymnasium was razed in 1907 to make way for Campbell Hall.

Bonner and Marquand also paid for the little boathouse that was built on the Delaware and Raritan Canal in 1874.