The Kentucky & Indiana Bridge (K&I Bridge) is one of the first multimodal bridges to cross the Ohio River. It was designed for both railway and roadway purposes, although the roadway has been closed since 1979. The K&I Bridge connects Louisville, Kentucky, to New Albany, Indiana.

Constructed from 1881 to 1885 by the Kentucky and Indiana Bridge Company, the original K&I Bridge opened in 1886. Federal, state, and local law state that railway, streetcar, wagon-way, and pedestrian modes of travel were intended by the cities of New Albany and Louisville, the states of Kentucky and Indiana, the United States Congress, and the bridge owners. It included a single standard gauge track and two wagon ways, allowing wagons and other animal powered vehicles to cross the Ohio River by a method other than ferry for the first time. At that time, motorized vehicles were virtually nonexistent. The K&I Bridge company also owned a ferry boat operation during both the first and second bridge; eventually that operation was sold as the bridge's success largely outmoded boat usage.

The Kentucky & Indiana Bridge, which spans the Ohio River at the Falls of the Ohio, was designed to connect the cities of New Albany, Indiana and Louisville, Kentucky, and to bring their residents closer together. Citizens of New Albany and Louisville who conceived the bridge described its purpose in the Articles of Association for the Kentucky and Indiana Bridge Company filed with the recorder of Floyd County, Indiana, on March 7, 1881. The bridge founders declared that the object and purpose of the company was to construct, own, and operate a bridge from a point in the city of New Albany across the Ohio River to a point in the city of Louisville for both railway and common roadway purposes together. The bridge and its approaches cost $1,500,000.

The alignment of the K&I is along America's ancient roads known as the Great Buffalo Trace and Wilderness Road. People have crossed at the limestone and coral rapids for 8,000 years. This strategic location has the only waterfall cascade on the 1,000-mile (1,600 km) Ohio and Mississippi River. In Louisville, this route offered the most rapid connection to U.S. Route 150 or Dixie Highway heading southwest and Lexington Road heading southwest. In Indiana the road follows the original route of the Buffalo Trace between Vincennes and New Albany. Each level of government, federal, state, and city, preserved its right of way and established speed limits across the bridge. In doing that, Louisville city leaders also mandated that the purpose of the bridge was for four modes of transportation: railroad, streetcar, vehicle, and pedestrian purposes. The city of Louisville and Federal Government also declared the K&I Bridge a postal route and retained its right of way in perpetuity.

Designer Mace Moulton, a member of the American Society of Civil Engineers, highlighted the K&I Bridge design, which included safety innovations, at the National Conference of the American Society of Civil Engineers in 1887. He chose the Ohio River location in Louisville across the Falls of the Ohio, where it has the least width. This gave residents of New Albany and Louisville a shorter and independent entrance to their cities. The railroad track was placed in the center between two trusses with a roadway on the outside of each truss, supported on projecting brackets, and with sidewalks on either side of the railroad track and inside the main trusses. Designers used high visual screens along the roadway to calm horses and livestock and to keep drivers focused on the roadway and not distracted by trains. On both the Louisville and New Albany sides, the common roadway and railway tracks are grade separated or completely independent.

Publicity for the opening of the Kentucky and Indiana Bridge was substantial as even the Library of Congress joined in advertising the grand opening of the bridge. It wrote: "There is in the course of construction at this time (1885), and about completed, a bridge across the Ohio, between Louisville and New Albany, Indiana. The bridge at Louisville is to have a railroad track, a passageway for the vehicles, streetcars, and a walk-way for foot passengers."

Kentucky & Indiana Bridge had a remarkable safety rating. Experts at the time ranked it among the safest of any major bridge in the United States. This was due to the narrow roadway lanes that induced slow driving speed and grade-separated crossings that kept the trains and roads on different vertical elevations where the road and rail routes crossed. The K&I Bridge Board of Directors reported, "The common roadway has been operated with remarkable freedom from accidents. The few that have occurred have been of trivial character with no loss of life or limb to any person."

Upon opening, the bridge company also offered the Daisy Line, an early steam locomotive commuter train service. In 1893, the Daisy Line trains became electrified, the first steam to electric conversion in the U.S. Passengers traveled in multi-unit three-car elevated electric trains from 1st, 4th, and 7th Street elevated stations and other stations en route between Louisville and New Albany. This rapid transit service was wildly popular, with its 15-minute service and convenient schedules, ridership soared from day one. By 1906, a ridership survey found 3,425 commuter passengers crossing daily and 1,250,000 passengers per year, crossing the K&I Bridge on these rapid electric trains.^{[citation needed]} Even by modern standards this would be considered a heavily used line.