Highest and Lowest Interstate

[Kacie Jane]

The lowest interstate in Washington is almost certainly I-5 where it gets down towards Kelso- that's basically sea level right there.

Nosing at Google Earth shows that I-5 only gets to the single digits in elevation closer to Woodland than Kelso.  But feel free to question its accuracy; it gives the elevation of the I-90 floating bridge at ~1 foot, when any other source I can find lists Lake Washington's elevation at around 16 feet.

[cpzilliacus]

Not sure about New Jersey. If I was to guess the highest would probably be somewhere in the western part along I-78 or I-80. The lowest would probably also be I-78 in the Holland Tunnel.

Another highest possibility would be I-287 in the north. I tried checking, but:
* Google Maps is stuck in Preview mode, which doesn't show Terrain lines dark enough or at the necessary zoom level

Some of the contour lines seem to be missing in Google, but that section of I-287 south of the New York/New Jersey border appears to be between 700' and 800' in elevation.

[hotdogPi]

Seems like in Massachusetts, the highest is the Mass Pike.

Beaten by MA 2, however, with 2000 feet.

Are there any other major routes in Massachusetts (maybe US 7) that are higher than MA 2?

[mgk920]

Highest in WI has to be near Baldwin (near Eau Clare) on I-94
Lowest - I-43 in Green Bay

Actually, I'm thinking that the highest in WI would be somewhere on I-39 in the Wausau area (near the CWA airport?), while the lowest would be I-90 at the Mississippi River in La Crosse.

Remember that the lowest point in Wisconsin is at the Illinois state line where it meets the Mississippi River shoreline.

Mike

[CNGL-Leudimin]

Which in turn means the lowest point in WI is close to the WI/IL/IA tripoint near Dubuque IA.

I cannot believe the highest point in the interstate system, the Eisenhower tunnel on I-70 in CO, is just 10 feet shorter than the highest peak in my region . But wait till China builds a couple of expressways through the Tibet, they will go up of 17,000 feet above sea level!!!

[english si]

But wait till China builds a couple of expressways through the Tibet, they will go up of 17,000 feet above sea level!!!

I doubt China will build more than one, and they chose rail rather than road when the 'bring the wild west closer to the east' plan took place. Urumqi got roads, not rail, so a Tibetan expressway isn't too likely.

[triplemultiplex]

Actually, I'm thinking that the highest in WI would be somewhere on I-39 in the Wausau area (near the CWA airport?), while the lowest would be I-90 at the Mississippi River in La Crosse.

For highest point, we may have a tie.  Both I-94 by exit 28 (WI 128) and I-39 by the airport in Mosinee touch a 1280' contour.  Someone needs to verify in the field!

Remember that the lowest point in Wisconsin is at the Illinois state line where it meets the Mississippi River shoreline.

Not true.
Normal pool elevation of the Mississippi at Dubuque below lock and dam number 11 is 592 feet above MSL.  The surface of Lake Michigan is 577 feet above MSL.

[mgk920]

Actually, I'm thinking that the highest in WI would be somewhere on I-39 in the Wausau area (near the CWA airport?), while the lowest would be I-90 at the Mississippi River in La Crosse.

For highest point, we may have a tie.  Both I-94 by exit 28 (WI 128) and I-39 by the airport in Mosinee touch a 1280' contour.  Someone needs to verify in the field!

Remember that the lowest point in Wisconsin is at the Illinois state line where it meets the Mississippi River shoreline.

Not true.
Normal pool elevation of the Mississippi at Dubuque below lock and dam number 11 is 592 feet above MSL.  The surface of Lake Michigan is 577 feet above MSL.

If that is indeed the case, then the lowest would be on I-43 for a distance eastward from its interchange with US(I)-41 (Howard Interchange).  I-794 is elevated over its entire length, I-43 and 94 in Milwaukee County are all above the bluffs while that part of I-43 in the Green Bay area runs low through a swampy shoreline area.  East of the Fox River bridge, the lowest parts of I-43 are on higher fill.

Maybe I was thinking of Illinois here - the lowest point in IL is at the Mississippi-Ohio River confluence in Cairo.  That should make I-57 in that area the lowest I-route in Illinois.

Mike

[yakra]

Maine:
Low: I-295 at the gores at the north side of Exit 7.
High: I-95 at roughly Mile 289.

[Landshark]

The lowest interstate in Washington is almost certainly I-5 where it gets down towards Kelso- that's basically sea level right there.

Nosing at Google Earth shows that I-5 only gets to the single digits in elevation closer to Woodland than Kelso.  But feel free to question its accuracy; it gives the elevation of the I-90 floating bridge at ~1 foot, when any other source I can find lists Lake Washington's elevation at around 16 feet.

I would guess that the lowest elevation on I-5 in Washington is where it crosses the Snohomish River Delta between Everett & Marysville.   That area is wetlands that were reclaimed by levees and the elevation is as low as 2 feet in places.    I-5 would have to dip below the level of the Columbia River to get to single digits in elevation up river from Longview. 

I-5's highest point in Washington is where it crosses Chuckanut mountain just south of Bellingham.

[CtrlAltDel]

I've done some digging around, and I can say with some confidence that the lowest point on the Interstate Highway System in Illinois is 298 feet, on I-57, where it crosses the Mississippi River near Cairo.

The highest point is 976 feet, on I-90, just east of its junction with US-20 near Hampshire.

Coming in second is 939 feet, on I-88, just east of its junction with I-39 near Rochelle.

That's a total variation of less than 700 feet.

[mgk920]

Actually, I'm thinking that the highest in WI would be somewhere on I-39 in the Wausau area (near the CWA airport?), while the lowest would be I-90 at the Mississippi River in La Crosse.

For highest point, we may have a tie.  Both I-94 by exit 28 (WI 128) and I-39 by the airport in Mosinee touch a 1280' contour.  Someone needs to verify in the field!

Remember that the lowest point in Wisconsin is at the Illinois state line where it meets the Mississippi River shoreline.

Not true.
Normal pool elevation of the Mississippi at Dubuque below lock and dam number 11 is 592 feet above MSL.  The surface of Lake Michigan is 577 feet above MSL.

If that is indeed the case, then the lowest would be on I-43 for a distance eastward from its interchange with US(I)-41 (Howard Interchange).  I-794 is elevated over its entire length, I-43 and 94 in Milwaukee County are all above the bluffs while that part of I-43 in the Green Bay area runs low through a swampy shoreline area.  East of the Fox River bridge, the lowest parts of I-43 are on higher fill.

Maybe I was thinking of Illinois here - the lowest point in IL is at the Mississippi-Ohio River confluence in Cairo.  That should make I-57 in that area the lowest I-route in Illinois.

Mike

One more thought here, what is the elevation of US(I)-41 at the top of that hill between WI 60 and WI 144 in Slinger?  That is the highest point on US 41 north of Tennessee.

Mike

[webfil]

The highest point on the Interstate Highway System is at the Eisenhower Tunnel on Interstate 70 in the Rocky Mountains of Colorado, at the Continental Divide (elev. 11,158 ft/3,401 m).

The lowest point on land is on Interstate 8 at the New River near Seeley, California (elev. -52 ft/−16 m).

The lowest point under water is on Interstate 95 in the Fort McHenry Tunnel under the Inner Harbor in Baltimore, Maryland (elev. -107 ft/−33 m).

Source: Wikipedia

In Québec, quite a few autoroutes lick the 400 metres (1,300 feet) contour line (A-10 near Orford mountain, A-15 south of Sainte-Agathe-des-Monts, A-73 at its northern end near Jacques-Cartier National Park entrance.

If the A-73 is ever applied to R-175 through Laurentides Park, that would break any mark, setting it at 940 metres (3,100 feet) near Montmorency forest. Upon completion, A-85 will reach 430 metres (1,400 feet) near Saint-Honoré.

The lowest autoroute is probably A-20 in Rivière-du-Loup, at sea level, through the intertidal zone.

(Not interstates, I know)

[Wadsteckel]

I-26 near the TN/NC border goes through Sam's Gap at 3,770 ft.  Wouldn't this be the highest interstate point east of the Mississippi River?

-Ed S

[ilpt4u]

I've done some digging around, and I can say with some confidence that the lowest point on the Interstate Highway System in Illinois is 298 feet, on I-57, where it crosses the Mississippi River near Cairo.

The highest point is 976 feet, on I-90, just east of its junction with US-20 near Hampshire.

Coming in second is 939 feet, on I-88, just east of its junction with I-39 near Rochelle.

That's a total variation of less than 700 feet.

We are flat-landers in the Prairie State, what can I say?

Oh, and I've driven all 3 of those points!

[inkyatari]

I've done some digging around, and I can say with some confidence that the lowest point on the Interstate Highway System in Illinois is 298 feet, on I-57, where it crosses the Mississippi River near Cairo.

The highest point is 976 feet, on I-90, just east of its junction with US-20 near Hampshire.

Coming in second is 939 feet, on I-88, just east of its junction with I-39 near Rochelle.

That's a total variation of less than 700 feet.

We are flat-landers in the Prairie State, what can I say?

Oh, and I've driven all 3 of those points!

Second flattest in the US!

[jon daly]

I-26 near the TN/NC border goes through Sam's Gap at 3,770 ft.  Wouldn't this be the highest interstate point east of the Mississippi River?

-Ed S

Thanks for reviving this thread, It's a good read.

[US 89]

Since this thread got bumped, I'll do Utah.

The highest interstate in Utah is I-70 over Emigrant Pass (between Salina and Fremont Junction), which is also its crossing of the Great Basin Divide. The elevation of this pass varies depending on who you ask, but Google Earth puts it at 7849 feet.

The lowest point is on I-15 in St George, at the bridge over the Virgin River in Washington County near St. George. Google Earth gives an elevation value of approximately 2550 feet.

Come to think of it, I-15 is the only interstate in Utah that even drops below 4000 feet. I-70 comes closest, getting to about 4050 feet at the Green River bridge. I-80, 84, and 215 all have low points in the vicinity of 4220 feet, near the Great Salt Lake which sits at 4200 feet on average.

[CtrlAltDel]

Second flattest in the US!

How so?

[inkyatari]

Second flattest in the US!

How so?

This article explains it...

https://news.nationalgeographic.com/news/2014/03/140314-flattest-states-geography-topography-science/

http://www.disruptivegeo.com/blog/wp-content/uploads/2014/08/FlatMap_GeographicalReview_DobsonCampbell_2013Nov.pdf

[TheHighwayMan3561]

MN:

Highest: I-90 west of Worthington (1,702)
Lowest: I-35 along the Duluth lakeshore (618)

[frankenroad]

In Ohio, the highest point appears to be around MP 167 on I-71 a few miles south of Mansfield, at just under 1400 ft.   The lowest, both at about 490 ft, are where I-275 crosses into Indiana and the Ft Washington Way Trench of I-71 in Cincinnati.

I don't know if Ohio has signed it on other routes, but on I-75 there are signs where you cross from the Ohio River watershed to the Lake Erie Watershed, around MP 106.

[jon daly]

Second flattest in the US!

How so?

This article explains it...

https://news.nationalgeographic.com/news/2014/03/140314-flattest-states-geography-topography-science/

http://www.disruptivegeo.com/blog/wp-content/uploads/2014/08/FlatMap_GeographicalReview_DobsonCampbell_2013Nov.pdf

That was an interesting link from NatGeo, but it seemed like the article ended abruptly. The .pdf is better. I'm not 100% on board with how the authors define flatness. I think that I'd weigh Percentage of State Area in Flattest Category very highly and move LA up to #2 and WY down to the bottom 5, but I'm not a geographer.

[jp the roadgeek]

Ok, I'll try CT for interstates

Highest point: I-84 in Middlebury between Exit 16-17 is about 750 feet above sea level.  Just beats out I-84 between Exit 68 and 69 in Tolland (about 720 feet)

Lowest point: I-95 in New Haven right along Long Wharf.  Can't be much more than 5 feet above sea level.

And RI:

High point: I-95 in West Greenwich just south of the RI 102 interchange is about 500 feet above sea level

Low point: I-95 in downtown Providence is about 20-30 feet above sea level. If it were not on a high bridge, I-195 at the Providence River would be the lowest. 

[texaskdog]

I wonder which potential interstate frustrated engineers the most