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No matter what town you go to in the U.S. --not matter how remote -- there's bound to be a post office nearby.

From a boat that delivers mail along the docks of a 29-mile stretch of  river, to aircraft that fly directly the coldest regions of Alaska, the country's post offices have been set up to meet the changes to the mail delivery system --and the people it serves.

"They are our history. This country expanded in every direction and while a large percentage of the population flocked to centralized locations that became large urban cities, a sizeable percentage remained in rural America and are there today. They receive U.S. mail delivery, like everyone else," Sue Brennan, U.S. Postal Service representative, told FoxNews.com.

As unique the locations, so too are some of the buildings. Some post offices are grand, decorated with granite columns and marble floors, while others are no bigger than a closet, while others still act as de facto town centers.

While post offices have come to mean long lines and frustrating service due to severe USPS budget cuts, visiting the country's more unusual post offices can be a fun and well worth the trip.

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"I've found postmark collecting, as well as photographing post offices, to be a great way of documenting my travels across the U.S. A postmarked item tells you exactly where you've been and when you were there,"  Evan Kalish, a former graduate student at the University of Pennsylvania and editor of Going Postal, told FoxNews.com.

Kalish has made it his mission to visit as many post offices as possible. So far he's seen about 4,000, and documents his travels on his blog.

We asked him to tell us which post offices are the quaintest, coolest, largest, and weirdest post offices across the U.S. You may want to take a look on your next road trip, before they're closed for good.

Kalaupapa and Hoolehua, H.I. 

These two offices are located in some of the best tropical spots in the United States, but that's not the only reason to visit these post offices.  Both have unique traditions that can't be found at other locations.

Why visit: Up until 1969, the Kalaupapa office served solely for a colony of 1,200 banished lepers, also known as Hansen's Disease. Nowadays, it only serves about 14 residents who are in remission thanks to sulfone drugs. While the site was studied for foreclosure, it is required to serve the community by law until the number of Hansen's Disease sufferers dwindles to zero. The site is highly restricted, but specific tours can be prearranged.

At the Hoolehua office, you can mail off a native-land coconut--no packaging necessary. Instead of a traditional piece of paper or post card, the Post-a-Nut program supplies visitors with a dried coconut. All you need to do is bring a marker to write the address, pay for postage, and the post office will do the rest. It's so unique that it was featured on National Geographic.

Learn more about these two offices here.

Ochopee, Fla.

The Ochopee, Fla., post office is the smallest post office in the nation. The 7x8-foot building, no bigger than a closet, used to be an irrigation pipe shed. It has no bathroom and services people in a 132 mile region. In 1953 the little shack it became the town's only post office after a fire destroyed the town's general store and post office. It's been running ever since.

Why visit: "It's along the way to the Everglades, it's great to sneak a peek before you go visit the alligators,"  Kalish told FoxNews.com.

Philadelphia, Penn.

The B. Free Franklin Station predates the American colonies and even the postal service. Although not a post office in 1975, the building was once the home of Benjamin Franklin, the country's first postmaster general. When you visit, be sure to get a special postmark of Benjamin Franklin's signature. It is the only post office that doesn't fly a U.S. flag — because the area pre-dates the Revolution.

Why visit: Last year the U.S. Postal Service was considering whether to close this site, but has decided to keep it open. You might want to visit it soon, just to be safe.

Supai, Ariz.

This office services the Havasupai Nation, a native American tribe located at the bottom of the Grand Canyon. Needless to say, the area cannot be accessed by automobile. So pack up and hike down or take a mule train down to the bottom of the canyon walls.

"Each mule carries about 130 pounds of mail, supplies and food down the 8-mile trail – averaging about 41,000 pounds per week," Brennan said.

Why visit: The area offers supreme views of stunning waterfalls and hikers use the post office to mail out their heavy parcels, rather carry them in or out of the canyon. Inside the office, see the unique walk-in freezers for food that will be delivered to remote locations.

Pine Ridge, Ark.

The town originally named Waters was officially changed to Pine Ridge after the popular radio show Lum and Abner was based on the town, but changed to names to Pine Ridge, on the air.  Henry M. Waters, a local businessman started a post office in his small store in 1886 and the town’s school and church operated in the same building. Now the post office also serves as the Lum and Abner Museum, and maintains the same building it did 100 years ago.

Why visit: While this on is a little bit obscure, and "you have to be up for an adventure," Kalish said it's still quite a unique treat. 

Agness, Ore.

This is one of only two towns in the United States that the mail is served by boat. While the town was originally supposed to be named Agnes, after the daughter of the first postmaster, it was misspelled and subsequently established by the post office as "Agness." The quaint community is best seen by boat tour in the summer months.

Why visit: "They take the mail boat 30 miles up to deliver the mail," Kalish said.

New York, N.Y.

The James A. Farley [Main] Post Office is difficult to top. The massive building occupies two full city blocks and is decorated with an impressive Corinthian colonnade.  It also bears the famous inscription: Neither snow nor rain nor heat nor gloom of night stays these couriers from the swift completion of their appointed rounds, which is often thought to be (incorrectly) as the official motto of the USPS. The bottom of the building is slated to become New York's new Moynihan Station, which will be a retro-futuristic hub located a block west of Penn Station.

Why visit: With grand columns and staircase, "you can't get any more grand or bold than this one," according to Kalish.

Bustins Island and Squirrel Island, Me.

These two post offices are on remote islands only accessible by ferry or by boat taxi.  The post office acts as the center of life in the community, and has art displays and places of people to come, visit and stay awhile.  "We had to pay for a fisherman to take us to the island," Kalish told FoxNews.com.

Why visit: Once you're there, send off an envelope for the Squirrel Island's unique postmark.

Learn more about these post offices here.

Chicago, Ill.

Old Chicago Main Post Office was the largest postal facility in the U.S. Even though it closed a few years ago, the outer facade is worth a look. The original structure was a brick-sided mail terminal building, but was expanded into a monstrous, modern-style structure.  "It was a sight to behold," Kalish chuckled.  Nowadays, the empty building is in the process of being sold. Also, try and spot parts of the building that were used for scenes in "Batman Begins", "The Dark Night", and "Transformers: Dark Side of the Moon."

Why visit: The architecture was thought up as the future of the postal service. This facility was built with a flat top to mail-servicing planes that could land directly on the building. While the concept never really flew off the ground, at the time the USPS figured would be more efficient than landing at the airport.

Texarkana, Ark.

The Half-n-Half Post Office is split down the middle between the state boundary of Texas and Arkansas. Once a courthouse as well as a post office, it stands today as a gray, rectangular building made out of Arkansas Limestone.

Why visit: It's the ultimate photo-op during a road trip. Who doesn't want to be in two places at once?

Washington, D.C.

See the National Postal Museum, that documents the historical progress of the USPS and its future. Just like all post offices--the museum is closest to its main mode of transportation, D.C.'s Union Station.

Why visit: See some of the rarest stamps, historical mechanisms of postal operations, and strangest modes of transportation used to deliver the mail.

Valentine, Tex., Christmas, Fla., Bethlehem, Penn. and  North Pole, Alaska

Maybe you won't want to visit these towns just for their names, but collecting their unique postmarks are a must.

For more information on unique and historical post offices, visit Evan Kalish's 'Going Postal' blog.