Highest and Lowest Interstate

[TheHighwayMan3561]

I wonder which potential interstate frustrated engineers the most

I can't imagine anything besides I-70. The tunnels, Glenwood, high mountain passes, just general mountain construction in general, the avalanches that affect the route every winter.

[jon daly]

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. 

DIGRESSION:

That's part of my commute. There are two weigh stations/rest areas nearby. The southbound one has been taken over by a construction company as a staging area. At first, I thought that it was for the nearby toll gantry, but that project ended months ago. Is there sitill some  nearby construction? This is a question that's been lingering in the back of my head for some time. Your post reminded me to finally ask that question.

[doorknob60]

Idaho

Lowest: I-90 at Stateline (WA border) - 2057 ft (Gonna be honest, I was expecting I-84 at Ontario, OR border to be the lowest; it's about 80 ft higher)

Highest: I-15 at Monida (MT border) - 6870 ft

Interesting thing is that there are a lot (well okay, a lot of it is remote canyons) of areas in Idaho with lower elevation than 2057 ft, but interstates go nowhere near them. The lowest (both the lowest highway, and the lowest point in the entire state, period) being Lewiston, roughly 720 ft on US-12 crossing into WA (sources say 710 ft at river level).

Looks like the highest point on a state highway in ID is Galena Summit on ID-87 between Ketchum and Stanley, 8,701 ft. Though I could be missing something there.

I have been to all 4 of those points, so yay.

[skluth]

Wouldn't be surprised if I-10's lowest point nationally was this location:

http://www.southeastroads.com/louisiana001/i-010_wb_exit_231b_03.jpg

The Railroad Underpass of Doom - Likely the lowest point in a city which itself is about 50% below sea level.

So low in elevation and so flood prone, the S&WB built a massive pumping station especially to drain the location (the square tan structure visible in the background).

I-10 east of Indio, CA, is about 40 ft BSL. I believe New Orleans only gets down to 10-12 ft BSL.

Many people don't realize it wouldn't take much to have a salt water port in the Coachella Valley. The saddle between the Gulf of California/ Sea of Cortez and the Salton Sea is only about 40 ft ASL. Breach that and the entire Imperial Valley and the east end of the Coachella Valley are underwater.

[GaryV]

I didn't notice Michigan in this thread yet. 

Probably both the highest and lowest points are both on I-75.  Certainly the lowest is I-75 along Lake Erie.  I'd guess the highest is somewhere up near Gaylord.

[MNHighwayMan]

Many people don't realize it wouldn't take much to have a salt water port in the Coachella Valley. The saddle between the Gulf of California/ Sea of Cortez and the Salton Sea is only about 40 ft ASL. Breach that and the entire Imperial Valley and the east end of the Coachella Valley are underwater.

Related: https://what-if.xkcd.com/152/

[Interstate 69 Fan]

Anyone know Indiana's?

[mgk920]

Anyone know Indiana's?

I would hazard guesses that both are in the southern part of the state, with I-164 in Evansville being the lowest.  Might a spot on I-69 southwest of Bloomington be the highest?

Mike

[CtrlAltDel]

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

It seems that flatness here is defined as "antisteepness," in that it's not the actual height differences that matter but how gently you get from one to the other. It's an interesting idea. Out of idle curiosity, I wonder how Olympus Mons, given the sheer size of its base, would fit in this schema.

[CtrlAltDel]

Anyone know Indiana's?

As far as I can tell, the low point, at 370 feet, is on I-69 near its terminus with US-41 in Evansville. The high point, at 1,116 feet, is on I-70 at the Ohio border.

[frankenroad]

I didn't notice Michigan in this thread yet. 

Probably both the highest and lowest points are both on I-75.  Certainly the lowest is I-75 along Lake Erie.  I'd guess the highest is somewhere up near Gaylord.

Without researching it, I would have to agree with you on both counts.

[yakra]

Maine:
Low point is on I-295, however many feet above sea level they filled in Back Cove to build the roadbed. Between exits 7 & 8. < 20 feet.
High Point is 740 feet, on I-95 just north of where it enters the town of Smyrna in Aroostook County.