US Road Map

US Road Map

About US Road Map

This road map of USA is showing US interstate highways, state highways with major cities and U.S. states.

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List of Interstate Highways in the United States

S.N.Interstate Highway NumberFormedLength in kmLength in mi
1I-9019564,988.553099.74
2I-8019564,666.442899.59
3I-4019574,114.462556.61
4I-1019573,959.532,460.34
5I-7019563,495.032171.71
6I-9519573,088.831919.31
7I-7519582,875.041786.47
8I-9419562,551.131585.2
9I-3519562,524.061568.38
10I-2019572,477.391539.38
11I-1519572,307.031,433.52
12I-519562,222.971,381.29
13I-2519571,708.591061.67
14I-5519601,551.81964.25
15I-6419611,550.64963.52
16I-6919571,464.66910.1
17I-6519581,427.97887.3
18I-8119611,376.02855.02
19I-8419801,238.58769.62
20I-2919581,215.88755.51
21I-8519581,071.90666.05
22I-4419581,024.65636.69
23I-771958981.86610.1
24I-491984881.15547.52
25I-741974871.65541.62
26I-571965819.03508.92
27I-591960716.53445.23
28I-761964701435.66
29I-301957590.24366.76
30I-81964560.45348.25
31I-711959556.14345.57
32I-791967552.75343.46
33I-871957536.7333.49
34I-261960528.01328.09
35I-241962509.13316.36
36I-391984492.68306.14
37I-911958467.31290.37
38I-451971458.52284.91
39I-861999408.81254.02
40I-841963374.51232.71
41I-222012325.44202.22
42I-961959309.09192.06
43I-431981308191.55
44I-891960307.58191.12
45I-42proposed310190
46I-931957305.69189.95
47I-761975300.11186.48
48I-721970288.54179.29
49I-412015281.64175
50I-161966268.45166.81
51I-781957235.41146.28
52I-171961234.85145.93
53I-821957231.07143.58
54I-371959230.14143
55I-881987226.27140.6
56I-41959212.92132.30
57I-271969206.53128.332
58I-881968189.5117.75
59I-681991182.1113.15
60I-731997162.7101.1
61I-991998158.2698.34
62I-121967137.7485.59
63I-831959136.8485.03
64I-661961122.7676.28
65I-191972101.9563.35
66I-861980101.1562.85
67I-11201786.7453.90
68I-2201375.3246.8
69I-42202450.731.5
70I-14201740.3925.10
71I-97198728.3617.62
72I-87201720.7612.9


US Interstate Highways


The Dwight D. Eisenhower National System of Interstate and Defense Highways operates as the fundamental network of road transportation throughout the United States. The highway network extends 48,000 miles throughout the United States in 2024 making it the largest highway system worldwide. The system functions to enable fast and extended travel between major cities throughout the contiguous 48 states while passing through mountainous terrain and flatlands and desert regions and coastal regions. The Interstate system functions as a vital transportation network because it supports both domestic travel and commercial logistics and emergency evacuations and military defense operations. The Interstate system works alongside the U.S. Route system by providing direct routes with controlled access points and minimum speed requirements.

Historical Background and Development

The idea of a national highway network originated during the early 1900s yet construction started after World War II. The Federal-Aid Highway Act of 1956 signed by President Dwight D. Eisenhower provided $25 billion to build 41,000 miles of Interstate highways during ten years. The large-scale infrastructure development found its initial motivation in Eisenhower's experience with German autobahns during World War II as well as his 1919 military convoy across America. The system evolved from its initial purpose of defense and economic growth to become vital for suburban development and national trade and everyday commuting.

Design Standards and Numbering

The construction of interstate highways follows specific requirements which include two lanes per direction and medians or barriers between traffic and limited access through interchanges and safety curves. The Interstate numbering system operates according to a grid pattern where east-west routes have even numbers with southern routes having lower numbers than northern routes and north-south routes have odd numbers with western routes having lower numbers than eastern routes. The primary Interstate routes use one or two digit numbers like I-5 or I-95 but auxiliary routes which include urban-serving spurs and loops use three-digit numbers such as I-405 or I-295.

Economic and Social Impact

The Interstate Highway System has had a profound effect on American life. It revolutionized interstate commerce, slashed travel times, enabled suburban growth, and increased regional connectivity. The U.S. Department of Transportation reports that Interstates account for more than one-quarter of all vehicle miles traveled throughout the country even though they represent only one percent of public roads. The system enables the transportation of more than 70 percent of the nation's valuable freight. The placement of major interstates near cities has led to substantial economic growth but rural areas now have better access to healthcare services and markets.

Current Statistics and Future Outlook

The Interstate system has more than 250 routes as of 2024, with I-90 being the longest (stretching approximately 3,020 miles from Seattle, Washington to Boston, Massachusetts). The shortest is I-878 in New York, less than one mile long. Ongoing infrastructure bills and modernization projects aim to upgrade aging bridges, incorporate smart technology, and enhance safety. Future development is also being influenced by environmental concerns and shifting transportation habits, including considerations for electric vehicle infrastructure and improved public transit integration.

The Interstate Highway System remains a fundamental component of the United States’ geography, economy, and daily life, determining how people and goods move across this vast nation.