The Delaware and Bound Brook Railroad Company was incorporated in New Jersey on May 12, 1874, for the purpose of forming a second railroad route between the cities of New York and Philadelphia.

The Delaware & Bound Brook was a successor to the National Railway project of 1868-1875. In 1831, the Camden & Amboy Railroad & Transportation Company was granted the exclusive right to operate a railroad across New Jersey between New York and Philadelphia. This monopoly expired in 1869, but the Camden & Amboy and its successor, the Pennsylvania Railroad, were able to use their control of the New Jersey State Senate to block any attempt to charter a competing line.

In 1868, a group of speculators led by Henry M. Hamilton attempted to evade this blockade by using existing charters for short railroads which could be joined end-to-end to form the desired route. As the consolidation stood on very flimsy foundations, the road's backers were forced to obtain legislative sanction. In 1871, they concealed a clause granting the required powers of consolidation in an otherwise unrelated bill for the German Valley Railroad Company, but the strategem was discovered. In 1872, they tried the same trick with the charter of the Stanhope Railroad Company, but this time concocted an elaborate fraud. Two bills were drawn up, one with and one without the enabling clause. By bribing the clerks of the legislature, the speculators were able to substitute the doctored bill only at those points in the process where it was required to be recorded and signed. The fraud was not discovered until after the bill was passed, but the Stanhope charter was eventually voided by the courts.

Next, Hamilton obtained a charter for a holding company, the National Company, from the more pliable Pennsylvania legislature. The National Company was authorized to hold the stocks of all the separate New Jersey lines. Meanwhile, the reaction to the Stanhope fraud helped anti-PRR forces in New Jersey finally secure the passage of a general railroad law, ending the need to apply to the legislature for special charters. Hamilton and his associates promptly formed companies under the general law, while the PRR formed companies of its own to pre-empt the ground and otherwise interfere with the National Railway. The taint of scandal, followed by the Panic of 1873, prevented Hamilton from completing his task.

At this point, the more responsible backers of the National Railway project broke away from Hamilton and joined with Edward Collings Knight and the North Pennsylvania Railroad to complete the project. The portion of the line west of Delaware River was built by the North Penn under its own charter. The Delaware & Bound Brook was formed to build the middle section, while the existing line of the Central Railroad of New Jersey was substituted for a new railroad between Bound Brook and Jersey City.

Fighting to preserve its lucrative monopoly, the PRR fought the Delaware & Bound Brook in the courts. It also built a line of its own in the same territory and blockaded the point at which the two tracks would have to cross. This resulted in the so-called "Frog War," the special rail pieces for crossings being known as frogs. Delaware & Bound Brook work gangs stormed and took the PRR position and defended it long enough to install the frog and obtain the protection of the local residents and the state militia.

The Delaware and Bound Brook inherited all of the rights and charters of the National Railway project in 1875. The so-called Bound Brook Route or "New Line" was opened for business on May 1, 1876, in time to profit from the Centennial traffic. A short branch was constructed to Trenton in 1877. Both the North Penn and the Delaware & Bound Brook were leased by the Philadelphia & Reading Railroad Company on May 14, 1879. Under Reading operation, the Bound Brook Route received deluxe equipment and after 1885 was operated at very high speeds, with short bursts as high as 100 mph. It also became the New York entrance of the Baltimore & Ohio Railroad.

The East Trenton Railroad Company was incorporated on April 17, 1884, and constructed a branch to the factory district of Trenton. It was merged into the Delaware & Bound Brook on December 9, 1955.

The company sold its railroad property to Conrail on April 1, 1976, and was finally liquidated in 1982.