US Highway 24 (US 24) is a United States Numbered Highway that runs from Minturn, Colorado, to Clarkston, Michigan. In Michigan, it is also known as Telegraph Road and runs for 79.828 miles (128.471 km) as a major north–south state trunkline highway from the Ohio state line through Metro Detroit. The highway runs through three counties in southeastern Michigan, Monroe, Wayne and Oakland, as it parallels the Lake Erie shoreline and bypasses Metro Detroit on the west. Telegraph Road connects several suburbs together and passes through the western edge of Detroit before it terminates northwest of Clarkston at an interchange with Interstate 75 (I-75).

The northern part of the highway follows a section of an old Indian trail called the Saginaw Trail that connected Detroit with points further north. The southern sections in the Downriver area south to Monroe parallel telegraph lines from the mid-19th century. These lines gave the road its name. Later this road was added to the state highway system in the early 20th century. It was upgraded and extended during the 1920s to serve as a western bypass of Detroit. The US 24 designation was applied to the highway on November 11, 1926, when the United States Numbered Highway System was inaugurated. Since that time, an alternate route, Alternate US Highway 24 (ALT US 24) was designated between the state line and the Gibraltar area; this highway later became part of I-75. In the 1970s, the northernmost section gained the US 10 designation when that highway was rerouted. That overlap was eliminated in 1986, and US 24 was extended north to Clarkston to replace a segment of US 10. At the same time, a business loop in Pontiac was redesignated for US 24 in addition to its connector routes it has.

Like other state highways in Michigan, US 24 is maintained by the Michigan Department of Transportation (MDOT). In 2011, the department's traffic surveys showed that on average, 85,302 vehicles used the highway daily between the "Mixing Bowl" and 12 Mile Road and 6,401 vehicles did so each day in southern Monroe County, the highest and lowest counts along the highway, respectively. All of US 24 north of I-275 is listed on the National Highway System, a network of roads important to the country's economy, defense, and mobility.

US 24 crosses the Ohio state line and follows Telegraph Road northeasterly through Monroe County. The highway runs parallel to the Lake Erie shoreline, farther inland than both I-75 (Detroit–Toledo Freeeway) or M-125 (Dixie Highway). The area around the trunkline is a mixture of farm friends and clusters of houses. Luna Pier Road connects US 24 to M-125 near Erie; this roadway is an unsigned highway called Connector US 24 (CONN US 24) that runs as a connector route between the two highways. Further north, US 24 passes to the west side of Monroe, meeting the eastern terminus of M-50 (Custer Road) near Custer Airport. The trunkline crosses the River Raisin near this intersection as well. North of Monroe near Stoney Creek, M-125 merges into US 24 and terminates. Further north, US 24 crosses I-275 before passing near the Flat Rock Speedway. The highway then crosses the Huron River and into Wayne County, entering the Downriver area.

Telegraph Road runs through downtown Flat Rock as it parallels the Lake Erie shoreline. North of the city in Brownstown Township, Telegraph Road and US 24 turn due north; a second CONN US 24 runs along Dix–Toledo Highway to connect US 24 to I-75 near Woodhaven. There is a third CONN US 24 in Taylor that provides access from southbound US 24 to southbound I-75 and from northbound I-75 to northbound US 24 between a pair of interchanges near the Southland Center. Telegraph continues northward through Taylor, widening into a boulevard and gaining a median. Traffic turning left onto the road needs to perform a Michigan left maneuver to do so, and drivers changing directions along US 24 have to use the U-turn crossovers in the median. From here north, the road runs through residential areas of the suburb approximately three miles (4.8 km) east of Detroit Metropolitan Airport, lined with various businesses immediately adjacent to the roadway. It crosses the South Branch of the Ecorse River. There are a pair of interchanges on US 24 for Ecorse Road and I-94 (Detroit Industrial Freeway), the latter being of the single point urban interchange (SPUI) design.

North of the Van Born Road intersection, Telegraph crosses into Dearborn Heights for the first time and over the North Branch of the Ecorse River. Past the river, the highway enters Dearborn. In the middle of its course through that city, US 24 crosses US 12 (Michigan Avenue) south of a branch of the River Rouge and the Dearborn Hills Golf Course. Telegraph crosses back into Dearborn Heights at the intersection with M-153 (Ford Road) east of St. Hedwig Cemetery. North of the cemetery, in the a section of the Middle River Rouge Park, Telegraph crosses the middle branch of that river before entering the southeastern corner of Redford Township. There is an interchange for a boulevard section of Plymouth Road before US 24 meets I-96 (Jeffries Freeway) on a section of the border with Detroit.

To the northeast of the I-96 interchange is the Elisa Howell Park as US 24 continues due north along a segment of the Detroit–Redford Township boundary. The trunkline crosses into Detroit completely north of Fenkell Avenue, which is the 5 Mile location in the Mile Road System of Detroit. Telegraph runs through urban residential neighborhoods of Detroit's West Side flanked by various parks to its immediate east. Telegraph crosses M-5 (Grand River Avenue), one of the five principal avenues of the Detroit street plan, south of 7 Mile Road. When it crosses M-102 (8 Mile Road), US 24 leaves Wayne County and enters Oakland County.

Running through Southfield, Telegraph Road continues due north to a location between 9 and 10 Mile roads. There the highway curves to the northwest and back north to approach the "Mixing Bowl", a complex interchange near 11 Mile Road that includes connections to I-696 (Reuther Freeway) and M-10 (Lodge Freeway and Northwestern Highway). Between the Mixing Bowl and 12 Mile Road, Telegraph runs through a commercial district in Southfield, and north of 13 Mile Road, the highway forms part of the border between the city of Franklin and the village of Bingham Farms; this area is predominantly suburban residential subdivisions.

At 14 Mile Road, US 24 crosses into Bloomfield Township and begins to meander between the lakes of Oakland County's lake country. The highway turns to the northwest before crossing Square Lake Road (19 Mile) south of Pontiac. Square Lake Road forms part of Business US 24 (BUS US 24), a business loop that runs into downtown Pontiac; Telegraph Road bypasses downtown to the southwest and west. At the interchange with Orchard Lake Road on the border between Pontiac and Sylvan Lake, US 24 turns northward along Pontiac's western border as an undivided roadway. Telegraph intersects M-59 (Huron Road) on the border between Waterford Township and Pontiac.

North of the Summit Place Mall, Telegraph Road ends at the intersection with Dixie Highway and the northern end of BUS US 24 (Cesar Chavez Avenue). US 24 turns northwesterly along Dixie Highway, crossing into Waterford Township. The highway meanders again through lake country flanked by residential subdivisions of the township. South of Clarkston, US 24 intersects the southern end of M-15. US 24 bypasses the city to the west and terminates at an interchange with I-75.

In 1701, the first transportation routes through what became the state of Michigan were the lakes, rivers and Indian trails. One of these Indian trails, the Saginaw Trail followed a path from the Detroit area north to Saginaw; this trail ran along what is now Dixie Highway from Pontiac northwards.

Telegraph lines were first installed from the Detroit area south to the Monroe area in the mid-19th century with additional lines north to Pontiac completed around 1868. As these communication lines were installed, roadways were added as needed to proved access for maintenance. The parallel road from Dearborn south was named for these lines, becoming Telegraph Road. When the state initially signposted its state highways in 1919, Telegraph Road from the Ohio state line north to Dearborn was assigned the original M-10 designation. The same year, the Dixie Highway, an auto trail that ran south from Detroit to Miami, Florida, was extended through Pontiac northward to the Straits of Mackinac. The numerical highway designation was changed to US 24 when the United States Numbered Highway System was inaugurated on November 11, 1926.

Highway traffic coming north from Toledo was forced to pass through Detroit to get to points north at the time. To ease the congestion downtown, a westerly bypass was constructed in the 1920s. Between Flat Rock and Dearborn, the upgraded highway was opened in 1922, with an extension to Stoney Creek the following year. The new road was built north from Michigan Avenue to Grand River Avenue in 1924. The extension to the state line was finished in 1925, and the remainder to Dixie Highway north of Pontiac was done in 1930. At the time, US 24 was extended north to the corner of Telegraph and Square Lake roads, with M-58 routed along the western Pontiac bypass. The highway was widened into a multi-lane highway starting in 1936.

By 1945, a divided highway designated Alternate US 24 (ALT US 24) was opened from the state line north to Erie. This divided highway, now named the Detroit–Toledo Expressway, was extended in 1956 to Gibraltar, and the ALT US 24 designation was continued north to connect back to the mainline near Woodhaven. The former connection near Erie becomes a connector route, now part of CONN US 24 and CONN M-125. Additional segments of freeway are opened through 1958, and the I-75 designation is applied to the freeway the following year.

In the 1960s, officials with the Michigan State Highway Department, predecessor to MDOT, added median crossovers along Telegraph Road. These additions were used to eliminate left turns at intersections and shift traffic less than 350 feet (110 m) away from the intersection. The distance complicated traffic flow. Later this concept was refined and used at the intersection of 8 Mile Road and Livernois Avenue, becoming the first Michigan left intersection in the state.

In 1970, US 10 was moved from its previous routing along Woodward Avenue between Detroit and Pontiac to follow the Lodge Freeway. From the northern end of the Lodge to Square Lake Road near Pontiac, US 10 and US 24 were run concurrently along Telegraph Road. North of Square Lake Road, US 10 continued along Telegraph back to Dixie Highway as before. In 1986, US 10 was truncated to end at Bay City instead of continuing on to Detroit. In the process, Telegraph Road lost its US 10 co-designation, US 24 was extended to its current northern terminus near Clarkston and the previously existing BUS US 10 in Pontiac was redesignated to become a BUS US 24 instead.

On November 30, 2005, President George W. Bush signed the 2006 appropriations bill related to the US Department of Transportation and other agencies. Contained in that law was a provision that named a 30-mile (48 km) stretch of US 24 from I-96 to its northern end at I-75 the "Max M. Fisher Memorial Highway"; the highway was dedicated in May 2008. In June 2012, Governor Rick Snyder signed a bill from the Michigan Legislature that designated a section of Telegraph Road in Taylor for Cpl. Matthew Edwards, a member of the Taylor Police Department that was killed in the line of duty.

There are one business loop in Pontiac and three connector routes for US 24 in Michigan. The connectors run between US 24 and I-75 in Erie, Taylor and Woodhaven. There previously was an alternate route signed for US 24 between the state line and the Gibraltar area. This route was incorporated into I-75 in 1959.