Does anyone know of any cool places to road bike in MN?

Never done it, but that seneic stretch on 61 north from Duluth to Grand Marais looks pretty decent for riding. Looked like pretty wide shoulders up to Two Harbors and it seems to be a popular spot with riders as there are always people using it when I'm up there in June for Grandmas.
It may be in your backyard too, based off the UMDRunner name.

Another resource, scroll down a little way on this site and you'll find a ton of riding links: https://www.trails.com/tcatalog_trail...lid=BGM035-015

And if you want to give racing a shot, check out these sites:
https://mcf.net/index.php
www.wisport.org
(despite the Wisconsin connection there are a good number of races on the western side of the state within driving distance of MPLS and Duluth)

There are many. Can you narrow it down a bit?

I'm from Duluth

Frankly, I avoid Duluth. Routeslip may be your friend in that respect. I did the Gunflint last summer and it was a hoot. Winds were right and it was just about the fastest road ride I've ever done. I can give you a plethora of metro options as well. PM Jimbud too. He stalks the northern hinterlands.

Mesabi trail is a great ride! Longest trail i believe in the nation.

There's too many to list in the State, but around Duluth here's some suggestions.

The advice you got on Scenic 61 is good, by all means go ride that. Easy for you to get to and good riding.

If you like trails you have the Munger Trail to the south. Beginning in Proctor and running uninterrupted for 75 miles to Hinckley. https://www.dnr.state.mn.us/state_tra...ger/index.html To the north you have Gitchi Gami Trail, short but scenic ride along Lake Superior including Split Rock Light House. https://www.ggta.org/ The previous advice on the Mesabi Trail is good but be aware it's not finished. It has several stops and starts along the way, so it's not the longest trail in the nation yet, but maybe someday when it's all done it might claim that title. They are pretty good at keeping their website up to date. https://www.mesabitrail.com/maps/ Check it out for the complete sections.

I've ridden all of 61 from Beaver Bay to the border. The northern section (Cascade River and up) is very pleasant, the southern section is only for the hardiest of road riders with small shoulders, blind curves and 70mph semi trucks. The word "Monson" will become your new swear word after that bit.

I've always wanted to ride Hwy 1 Tettegouche to Ely, but can't actually comment on it's suitability.

Hwy 210 through Jay Cooke is fun for hill climbing. The road is in fairly poor condition to be ready for a flat or two.

Highway 23 (I've only ridden it south from 210 to Sandstone) was a fine ride.

Scot

I usually just ride wherever I feel like for the most part, but have a 3 fun century routes and tons of loops and out 'n backs.

Centuries/Longer rides:

(out and back) Duluth - Beaver Bay - Duluth. Don't do it in fall. Leafers with RVs are on a rampage. Elderly folk don't take kindly to slowing down for bikers or even putting their fold-down stairs up (I shudder when I think of catching some metal stairs in the back of the leg at 55mph). Shoulder is crap for a couple miles.

(loop) Duluth - Two Harbors - Pequaywan Lake - Duluth. Head up to Two Harbors, north on Hwy 2 to 14/cty55, then take cty44/Pequaywan lake road to Jean Duluth, which will bring you out by UMD. (make sure you map this one out ahead of time because my directions are not perfect and there is nothing for miles upon miles and a wrong turn would suck). Very few water stops. No shoulder for a good portion, but beautiful country. I did this one while exploring, hoping something would link up eventually, which it did.

(out and back) Duluth - Munger Trail - Willow/Kettle River and Back.

Other fun rides:

Over the Bong bridge to Superior for Anchor Burger or pizza and beer at the Thirsty Pagan.

Highland Street (West End). Bottom to top of hill, one street. (best if done on fixed/ss for maximum burn/puke factor).

The old railroad grade above the Munger Trail from West Duluth to Ely's peak. I've done the ride to Ely's Peak offroad on a road bike. After Ely's peak the trail turns to 2" rocks and is nearly impossible to ride without MTB tires (unless you like pinch flats).

Skyline from Becks Road to Seven Bridges Road. (be prepared for a hill workout and gravel).

Park Point at night in the winter. Right now you can cross the bay over to Superior.

Over to Oliver Bridge (far west end), up through Superior, back to Duluth over Bong bridge.

Plus tons of others.

Couple others:

Head out to Pike Lake, then to Esko, hook-up with Munger Trail (via gravel road), then back to Duluth.

There are some cool off road trails just outside of Jay Cooke on the Duluth side (need CX tires or a MTB), not sure on the conditions these days, but the last time I went, ATVs had more or less ruined what I used to consider the best MTB ride in the area... what used to be nice trail is now miles of ruts.

There is a new MTB trail opening up this spring off of skyline, not exactly sure of the location/details other than it is supposed to rock.

There are also a handful of trails inside of Jay Cooke, not sure on which ones allow bikes these days (used to ride before any were marked for just biking/hiking/horses etc.) Most could be ridden with a CX bike.

.... make sure the trails are not marked with blue paint, which denotes the Superior Hiking Trail. (unless the trail is specifically marked for both (not sure if there are any sections like this))

Anybody else have some suggestions for road routes in Duluth or the northeastern section of MN? I'm looking for something in the 100-150 mile range. I was messing around on Google maps and I came up with a few routes, but I have no idea what the roads are like. Any advice or alternate routes would be appreciated.

https://goo.gl/maps/Ztj9
https://goo.gl/maps/5o65
https://goo.gl/maps/Z0BZ

(If you know of any can't-miss routes near MSP, feel free to throw those in, as well.)

cross the river into the superior area..huge trail near there