City/town names that are ambiguous in your area

[mrsman]

Ambiguous enough that any mention will require the state name (or other region) to avoid being asked "which one".

Note that in most cases, this is extremely local to where you live.

Here, there are a few that are ambiguous, plus two that would be if I moved a few miles.
Concord (MA vs. NH)
Hudson (also MA vs. NH)
Birmingham (AL vs. UK)
Rochester (NH vs. NY; MN is not a contender)
Washington (the state itself vs. the country's capital)
Amherst (MA vs. NH)

Where I live, Salem without a state name refers to Salem, NH, but moving ≈5 miles south or southeast (the number 5 is a guess) would make it ambiguous enough, with the other option being Salem, MA. I frequently go places where Salem, MA is the default meaning.

Newton without a state name refers to Newton, MA, even though Newton, NH is much closer. My guess is that going north into New Hampshire will result in Newton, NH being the default meaning as soon as you cross the state border; to find an area where it is ambiguous, I would have to go into Haverhill, MA (which is adjacent to Newton, NH).

Others that might seem ambiguous where I live, but are not:
* Portland refers to ME, not OR. People will talk about the other Portland, but they'll almost always apply the state name.
* Dover refers to DE, not MA or NH. Crossing the state border probably changes this to NH without any region of ambiguity, but there has to be a region of ambiguity somewhere for MA vs. DE.
* Springfield refers to MA, which makes sense since the three major ones are somewhat similar in population, and the one in Massachusetts is much closer than the other two.
* Franklin refers to MA, not NH.
* Brookline: Same as Newton; the one in New Hampshire is closer, but the one in Massachusetts is always meant.
* Groton: MA, even though CT is larger.
* Kingston: Could be 4-way (NH, MA, NY, Jamaica), but "Kingston" by itself refers to NH here.
* Burlington: MA, not VT.
* Bedford: MA, not NH; probably changes immediately upon crossing the state border.
* Rutland: VT, not MA.
* Greenland: Refers to the dependency of Denmark, despite the one in New Hampshire being within 30 miles.

Haven't encountered Milford enough to know (if it was ambiguous, it would be MA vs. NH). Same with Augusta (ME vs. GA) and Orange (MA vs. CA).

In California, there are at least two or three cities or towns that sound like Arcata, Arcadia, or similar. There are two with the same exact name one on the North Coast and one in the LA area.

The term "The Valley" usually refers to "San Fernando" south of Santa Barbara, but to "The Great Central Valley" (often Fresno, Bakersfield, or Tracy, Stockton, Sacramento, Chico, or Redding, depending upon what part of the coast) north of there.

San Marcos refers both to a suburb of San Diego and a pass near Santa Barbara.

"Grapevine" is a small town at the extreme south end of the San Joaquin Valley, but is often used to refer to the entire grade on the Valley side of Tejon Pass (and sometimes to the entire section of freeway between Grapevine and Santa Clarita.

In a similar vein, within CA there are two Brentwoods, a town along CA-4 in Nor Cal, and a neighborhood in West Los Angeles, famous for being where OJ Simpson lived.

There are also two Richmonds, both in the Bay Area.  One in the east bay, a town north of Oakland, and the second was a neighborhood on the west side of San Francisco.  Given how close these two are, it can sometimes be quite confusing.

[thspfc]

Fox Lake, WI and IL is the only one I can think of.

[KEVIN_224]

There are 26 places named Springfield in the United States. The most prominent ones are Massachusetts, Illinois and Missouri. I-91 passes through Springfield, MA and Springfield, VT. The Vermont town won the right to premiere the Simpsons movie when it came out.

Besides Portland, ME and OR, there's also a Portland, CT. It's on the other side of the Connecticut River (and the Arrigoni Bridge) from Middletown.

Besides Hartford, CT, you also have one in VT and ME. VT's Hartford is "hidden" some because it contains the more prominent village of White River Junction.

[Brandon]

There are 26 places named Springfield in the United States. The most prominent ones are Massachusetts, Illinois and Missouri. I-91 passes through Springfield, MA and Springfield, VT. The Vermont town won the right to premiere the Simpsons movie when it came out.

Besides Portland, ME and OR, there's also a Portland, CT. It's on the other side of the Connecticut River (and the Arrigoni Bridge) from Middletown.

There's also a Portland, Michigan, along I-96 between Lansing and Grand Rapids.

Besides Hartford, CT, you also have one in VT and ME. VT's Hartford is "hidden" some because it contains the more prominent village of White River Junction.

Not to forget Hartford, Michigan, along I-94, and Hartford, Illinois, between I-270 and Alton.

[Big John]

Besides Hartford, CT, you also have one in VT and ME. VT's Hartford is "hidden" some because it contains the more prominent village of White River Junction.

Not to forget Hartford, Michigan, along I-94, and Hartford, Illinois, between I-270 and Alton.

and Hartford WI, at hwy 60 and hwy 83 west of I-41

[nexus73]

North Bend.  Oregon, Washington and Nebraska have one.  Then add in Bend and people thinking that North Bend refers to that city.

Port Orford.  There is only one.  However in Washington, there is a Port Orchard.  That name has more familiarity than Port Orford does.

Brookings.  One in Oregon and another in South Dakota.

Lakeside.  There has to be a ton of them!

Rick

[Rothman]

Which is not a municipality in New York?

Owego
Otego
Osego
Otsego
Oswego

[jp the roadgeek]

There are 26 places named Springfield in the United States. The most prominent ones are Massachusetts, Illinois and Missouri. I-91 passes through Springfield, MA and Springfield, VT. The Vermont town won the right to premiere the Simpsons movie when it came out.

Besides Portland, ME and OR, there's also a Portland, CT. It's on the other side of the Connecticut River (and the Arrigoni Bridge) from Middletown.

Besides Hartford, CT, you also have one in VT and ME. VT's Hartford is "hidden" some because it contains the more prominent village of White River Junction.

There's also a Portland, PA along the Delaware River, on the PA side of the Columbia-Portland toll bridge that connects PA 611 (and used to carry US 611) with I-80 and NJ 94. 

Milford, MA and NH were mentioned, but there is also a larger Milford, CT; the home of Subway, former home of Bic's US headquarters, and the Dan Patrick Show.

Also with Orange, lest us forget Orange, CT: the home of Pez Candy (and right next to Milford)

Also discovered a New Britain, PA along US 202; the first borough as you enter Bucks County from Montgomery.  Much smaller than its CT counterpart.  Also learned of a Southington, OH from when Mike Tyson was released from prison.  Much smaller and lesser known than the CT one.

Then there's a few Bristols: Bristol, CT (the home of ESPN); Bristol, RI; a pair of Bristol Counties in MA and RI; and Bristol, PA (the Bristol referred to in the Bristol Stomp).

And then we have Berlin, and it's appropriate pronunciation.  In CT, NH, and NY, it's BER-lin; in NJ, the syllables are equal, so it's essentially like two words (Burr Lynn), and in Germany, it's ber-LIN

Portsmouth can also be.  For New Englanders, it's usually the city in NH; a control city for I-95 and I-495, and with a commercial airport.  There is also the smaller one in RI next to Newport.  For those in the Mid-Atlantic, it's part of Hampton Roads in VA. 

A few more: Scituate (MA vs RI); Tolland (CT vs MA); Litchfield (CT vs NH); Westbrook (CT vs ME; both connected by I-95)

[inkyatari]

There are 26 places named Springfield in the United States. The most prominent ones are Massachusetts, Illinois and Missouri. I-91 passes through Springfield, MA and Springfield, VT. The Vermont town won the right to premiere the Simpsons movie when it came out.

Yet, the Illinois Springfield is the only one close to a Shelbyville.

[TBKS1]

Here's what immediately comes to mind for me...

Greenville, MS vs. Greenville, SC
Stuttgart, AR vs. Stuttgart, DE
Huntsville, AR vs. Huntsville, AL
Sheridan, AR vs. Sheridan, WY
Nashville, AR vs. Nashville, TN
Melbourne, AR vs. Melbourne, FL
Benton, AR vs. Bentonville, AR

As well as Norfork, AR vs Norfolk (UK and many states, but I'm sure that the one in Virginia comes to mind for almost everyone).

[zzcarp]

In Colorado, there is a front range city approximately 50 miles north of Denver called Loveland. About 60 miles west of Denver just before the Eisenhower-Johnson Tunnels there are Loveland Pass and Loveland Ski areas. There's no direct connection between the two.

[US 89]

In Colorado, there is a front range city approximately 50 miles north of Denver called Loveland. About 60 miles west of Denver just before the Eisenhower-Johnson Tunnels there are Loveland Pass and Loveland Ski areas. There's no direct connection between the two.

Along that same line, Berthoud is a north Front Range city (actually pretty close to Loveland) that is similarly far away from the pass of the same name on US 40. There's also a Berthoud Falls fairly close to the pass.

[TBKS1]

Here's what immediately comes to mind for me...

Greenville, MS vs. Greenville, SC
Stuttgart, AR vs. Stuttgart, DE
Huntsville, AR vs. Huntsville, AL
Sheridan, AR vs. Sheridan, WY
Nashville, AR vs. Nashville, TN
Melbourne, AR vs. Melbourne, FL
Benton, AR vs. Bentonville, AR

As well as Norfork, AR vs Norfolk (UK and many states, but I'm sure that the one in Virginia comes to mind for almost everyone).

Didn't even think about this originally...

Fayetteville, AR vs. Fayetteville, NC

Not sure which one gets more recognition, guess that's up to what you believe.

[CNGL-Leudimin]

Here's what immediately comes to mind for me...

Stuttgart, AR vs. Stuttgart, DE

DE as in .de (Deutschland, Germany)? Or there's a Stuttgart in Delaware I'm not aware of?

I'm pretty sure there is Madrid, IA/NY vs Madrid, Spain.

[roadman65]

Florida is pretty good about not being too redundant, but you have Edgewood, Englewood, and Edgewater all that can be confusing as the names are close.  Sometimes I mix up the city with location too!

We have both Seminole, the county near Orlando, and the city near St. Pete.  However that may not be what the OP is looking for due to one being not a city, and the fact Ohio and North Carolina both have city and counties that have the same names but no where near each other, so that may be more a common thing.

[TBKS1]

Here's what immediately comes to mind for me...

Stuttgart, AR vs. Stuttgart, DE

DE as in .de (Deutschland, Germany)? Or there's a Stuttgart in Delaware I'm not aware of?

I'm pretty sure there is Madrid, IA/NY vs Madrid, Spain.

Meant it as in Germany, not Delaware. Sorry if that was confusing.

[TheHighwayMan3561]

Virginia (MN) vs. Virginia (state). Twin Cities not so much an issue since they're more likely just to use the blanket Iron Range, but Duluth people usually have to differentiate between the two.

And yes, I was going to college an hour from Virginia, MN with a guy from Virginia, the state.

[royo6022]

Daviess County, IN (pronounced day-VEES) and Daviess County, KY (pronounced Davis)

[Beltway]

Virginia City, Nevada and Virginia City, Montana

[csw]

Daviess County, IN (pronounced day-VEES) and Daviess County, KY (pronounced Davis)

Another classic case of Hoosiers mispronuncicating things. (See: Versailles)

[frankenroad]

And a lot of people can't keep straight that the correct spelling of the island, the straits, and the bridge is Mackinac, but the correct spelling of the city is Mackinaw.

And they are ALL pronounced MACK-in-aw     It't like nails on a chalkboard to me when someone says "MACK-in-ack"

[roadman65]

Daviess County, IN (pronounced day-VEES) and Daviess County, KY (pronounced Davis)

Like in NY City, the street called Houston Street is pronounced How-ston as it was not named after Sam Houston, who Texas' largest city was named.  It was named after a man who spelled his name the same but used how instead of hew.

[kevinb1994]

Daviess County, IN (pronounced day-VEES) and Daviess County, KY (pronounced Davis)

Like in NY City, the street called Houston Street is pronounced How-ston as it was not named after Sam Houston, who Texas' largest city was named.  It was named after a man who spelled his name the same but used how instead of hew.

Actually the spelling should be HousTOUN, as that was the way he preferred it.

[NWI_Irish96]

Nothing much comes to mind in Indiana. But I still don't know which is which of Sioux Falls and Sioux City. And I always mix up Great Falls, MT, with Grand Forks, ND. And Billings and Bozeman. I'd probably get it if I ever went to Montana.

Columbus OH and IN, both served by interstates from Indianapolis. 
St. Joseph Counties IN and MI, not far from each other.
Plainfield IL and IN (only ambiguous if you've spent a lot of time in both Chicago and Indy metro areas)

I forgot to mention Lake Counties in Illinois and Indiana, which both border Cook County, IL.

[clong]

Birmingham was mentioned in the original post as one causing confusion. No one thinks you mean Birmingham, England for probably a 4 or 5 hour radius (at least) from Birmingham, AL unless you're having a discussion about soccer.

Same would be true about Huntsville. And the next most likely Huntsville would be Texas - known for conducting executions for those sentenced to the death penalty.