U.S. Route 30 (US 30) is a part of the United States Numbered Highway System that runs from Astoria, Oregon, to the Atlantic City, New Jersey. In Indiana, it is a State Road that enters the state between Lynwood, Illinois, and Dyer. The 155.96 miles (250.99 km) of US 30 that lie within Indiana serve as a major conduit. All of the highway is listed on the National Highway System. Various sections are rural four-lane highway and urbanized four-lane divided expressway. US 30 passes through farm fields and urban areas, and along the northern half of the state.

US 30 was first designated as a US Highway in 1926. A section of the highway originally served as part of the Lincoln Highway. US 30 replaced the original State Road 2 (SR 2) and SR 44 designation of the highway which dated back to the formation of the Indiana State Road system. SR 2 ran from Illinois state line through South Bend to Fort Wayne and ended at the Ohio state line. SR 44 ran from Valparaiso to Plymouth to Fort Wayne. Realignments and construction projects have expanded the highway to four lanes across the state.

US 30 enters Dyer from Lynwood, Illinois along the original alignment of the Lincoln Highway. The highway is four-lane divided highway, passing through mostly commercial properties. At Moeller Street in Dyer the roadway becomes a four-lane highway with a center turn lane. The route has an at grade crossing with the CSX Railroad tracks. The road becomes a four-lane divided highway before a traffic light at US 41 in Schererville. After US 41 the highway passes under the Norfolk Southern Railroad tracks. After US 41 the original alignment of the Lincoln Highway leaves US 30 and travel on old State Road 330 (SR 330). US 30 begins to curve towards the southeast, still as a four-lane divided highway. The highway has a traffic light at SR 55, heading east again, as the roadway enters Merrillville. The route becomes a six-lane divided highway and has an interchange at Interstate 65 (I–65). At Colorado Street in Merrillville the road narrows back to a four-lane divided highway.

The road has a traffic light at the southern terminus of SR 51 in Hobart and US 30 enters rural areas of Indiana. After SR 51 the original alignment of the Lincoln highway rejoins US 30. The highway passes through a mix of farmland and residential properties on the way to Valparaiso. The roadway enter Valparaiso passing through commercial properties and a series of curves. The highway has a traffic light at the western end of the SR 2 concurrency. The two highways passes over the Chicago, Fort Wayne, and Eastern Railroad tracks and the Norfolk Southern Railroad tracks. the concurrency passes south of the Valparaiso University and has a traffic light at the eastern terminus of SR 130. After passing the traffic light at SR 130, the road has a full interchange with SR 49 and the eastern terminus of SR 2 concurrency. After the interchange at SR 49, the road passes the Porter County Municipal Airport. The highway heads east-southeast from Valparaiso, towards Plymouth passing through rural farmland, with an intersection at US 421 and an at grade railroad crossing with the Chesapeake and Indiana Railroad. East of the railroad tracks is an intersection with SR 39 and an interchange at US 35.

The highway heads along the northside of Plymouth passing through an interchange with the northern terminus SR 17 and near the Plymouth Municipal Municipal Airport. The route begins to curve around the northeast side of town, having an interchange with US 31. US 30 leaves the Plymouth area, heading southeast towards Warsaw. On the way Warsaw the having an interchange at SR 331. The road curves east before entering Warsaw and has an interchange with SR 15, south of the Warsaw Municipal Airport. After passing the airport, the road enters a mix of commercial and residential properties and has a traffic light at an old alignment of the Lincoln Highway. The road passes north of Winona Lake and heads towards Columbia City, paralleling the Chicago, Fort Wayne and Eastern Railroad, passing through rural farmland. The roadway enters Columbia City from the west heading east, before turning southeast. In Columbia City the highway has a traffic light at SR 109, SR 9 and SR 205. After SR 205, US 30 heads east towards Fort Wayne, which again paralleling the Chicago, Fort Wayne and Eastern Railroad. The route crosses into Allen County at a traffic light at the Whitley-Allen County Line Road.

The highway enters Fort Wayne with a traffic light at Kroemer Road and a trumpet interchange with the western end of the US 33 concurrency. After the interchange the concurrency heads east-southeast towards an interchange with I–69 as a six-lane divided highway, passing through woodland with some commercial properties. At the interchange with I–69, US 33 heading south on I–69 and US 30 heading north on I–69. While concurrent with I–69 the roadway is a six-lane urban interstate with interchanges at Lima Road (US 27 and SR 3) and Coldwater Road (formerly SR 327 and US 27). US 30 leaves I–69 at the I–469 interchange heading east concurrent with I–469, towards New Haven. The highway is a four-lane interstate passing through a mix of farmland and residential properties. The route has a bridge over the St. Joseph River and an interchange at Maplecrest Road. After Maplecrest Road the highway turns south around the northeast side of Fort Wayne and has an interchange at SR 37 followed by US 24. After the US 24 interchange is a bridge over the Maumee River and the Norfolk Southern Railroad tracks. US 30 leaves I–469 east of downtown New Haven at the SR 930 interchange. After I–469, US 30 heads southeast away from New Haven passing through rural farmland with a few house, as a four-lane divided highway. The route has an intersection at SR 101, before entering Ohio. The road leaves Indiana for Ohio between New Haven and Van Wert.

The entire length of U.S. Route 30 in Indiana is included in the National Highway System (NHS). The NHS is a network of highways that are identified as being most important for the economy, mobility and defense of the nation. The highway is maintained by the Indiana Department of Transportation (INDOT) like all other U.S. Highways in the state. The department tracks the traffic volumes along all state highways as a part of its maintenance responsibilities using a metric called average annual daily traffic (AADT). This measurement is a calculation of the traffic level along a segment of roadway for any average day of the year. In 2010, INDOT figured that lowest traffic levels were 10,870 vehicles and 4,750 commercial vehicles used the highway daily between US 31 and SR 331. The peak traffic volumes were 69,280 vehicles and 12,660 commercial vehicles AADT along the section of US 30 at is concurrent with I–69, between the Lima Road and Coldwater Road exits in Fort Wayne.

The Lincoln Highway was planned from Illinois state line to South Bend to Fort Wayne and the Ohio state line, in 1913. In 1915, the highway open and passed through downtown Fort Wayne on its route through Indiana. In 1917 Main Market route number 2 was the given number to the Lincoln Highway in Indiana. The route became SR 2 from Illinois state line to Valparaiso, SR 44 Valparaiso to Fort Wayne and SR 2 from Fort Wayne to Ohio state line. In the early 1920s, the Lincoln Highway was moved farther south between Valparaiso and Fort Wayne, to what is now known mostly as Old US 30, passing through Plymouth and Warsaw. The part of US 30 in Dyer that is known as the ideal section of the Lincoln Highway was opened in 1923 and rebuilt in the 1990s. Then in 1924, the sections of the road that was part of the original Lincoln Highway was paved. The next few years the rest of the route was paved across Indiana and then in 1926 US 30 was commission. In 1927, a small realignment between Hanna and SR 29 (current US 35) took place. Before Coliseum Boulevard was built, in 1950s, the highway went through downtown Fort Wayne. When Coliseum Boulevard was built US 30 was reroute onto it, making a bypass around Fort Wayne. Then in 1998, US 30 was moved onto I–69 and I–469, bypassing most of Fort Wayne and New Haven on the north and east side of the two towns.