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 Number
Formed
Length in km
Length in mi
1
I-90
1956
4,988.55
3099.74
2
I-80
1956
4,666.44
2899.59
3
I-40
1957
4,114.46
2556.61
4
I-10
1957
3,959.53
2,460.34
5
I-70
1956
3,495.03
2171.71
6
I-95
1957
3,088.83
1919.31
7
I-75
1958
2,875.04
1786.47
8
I-94
1956
2,551.13
1585.2
9
I-35
1956
2,524.06
1568.38
10
I-20
1957
2,477.39
1539.38
11
I-15
1957
2,307.03
1,433.52
12
I-5
1956
2,222.97
1,381.29
13
I-25
1957
1,708.59
1061.67
14
I-55
1960
1,551.81
964.25
15
I-64
1961
1,550.64
963.52
16
I-69
1957
1,464.66
910.1
17
I-65
1958
1,427.97
887.3
18
I-81
1961
1,376.02
855.02
19
I-84
1980
1,238.58
769.62
20
I-29
1958
1,215.88
755.51
21
I-85
1958
1,071.90
666.05
22
I-44
1958
1,024.65
636.69
23
I-77
1958
981.86
610.1
24
I-49
1984
881.15
547.52
25
I-74
1974
871.65
541.62
26
I-57
1965
819.03
508.92
27
I-59
1960
716.53
445.23
28
I-76
1964
701
435.66
29
I-30
1957
590.24
366.76
30
I-8
1964
560.45
348.25
31
I-71
1959
556.14
345.57
32
I-79
1967
552.75
343.46
33
I-87
1957
536.7
333.49
34
I-26
1960
528.01
328.09
35
I-24
1962
509.13
316.36
36
I-39
1984
492.68
306.14
37
I-91
1958
467.31
290.37
38
I-45
1971
458.52
284.91
39
I-86
1999
408.81
254.02
40
I-84
1963
374.51
232.71
41
I-22
2012
325.44
202.22
42
I-96
1959
309.09
192.06
43
I-43
1981
308
191.55
44
I-89
1960
307.58
191.12
45
I-42
proposed
310
190
46
I-93
1957
305.69
189.95
47
I-76
1975
300.11
186.48
48
I-72
1970
288.54
179.29
49
I-41
2015
281.64
175
50
I-16
1966
268.45
166.81
51
I-78
1957
235.41
146.28
52
I-17
1961
234.85
145.93
53
I-82
1957
231.07
143.58
54
I-37
1959
230.14
143
55
I-88
1987
226.27
140.6
56
I-4
1959
212.92
132.30
57
I-27
1969
206.53
128.332
58
I-88
1968
189.5
117.75
59
I-68
1991
182.1
113.15
60
I-73
1997
162.7
101.1
61
I-99
1998
158.26
98.34
62
I-12
1967
137.74
85.59
63
I-83
1959
136.84
85.03
64
I-66
1961
122.76
76.28
65
I-19
1972
101.95
63.35
66
I-86
1980
101.15
62.85
67
I-11
2017
86.74
53.90
68
I-2
2013
75.32
46.8
69
I-42
2024
50.7
31.5
70
I-14
2017
40.39
25.10
71
I-97
1987
28.36
17.62
72
I-87
2017
20.76
12.9
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.
