Baltimare is among the list of locations in Equestria mentioned in various episodes of My Little Pony Friendship is Magic. It is obviously named after the real city of Baltimore, Maryland, where I was actually born and still live in it's vicinity.
This Equestrian location is my latest idea for MLP Friendship is Magic.
I presume that the Equestrian location of Baltimare includes not only the city of Baltimare but also miles of surrounding countryside. Both the city and the surrounding countryside are governed by an elected Governor-Mayor of Baltimare and an elected Baltimare Council. The Council can pass local laws, but the Governor-Mayor retains veto power.
Baltimare is located on the shore of Horseshoe Bay and the great ocean to the immediate east of Equestria. It's economy is largely based upon trade with foreign nations outside Equestria although Baltimare does have local farming and fishing industries, too. The manufacture of trains and railroad components is a major local industry as well. The fishing and agriculture make a relatively small contribution to the Equestrian food supply, but Baltimare controls a large portion of Equestria's international trade and manufactures the majority of the pony nation's railroad rails, steam engines, and train cars.
In the thousand-year period when Princess Luna was exiled to the Equestrian moon, the regime of Princess Celestia grew increasingly concerned about the anti-Canterlot bias of many local Baltimare politicians (including many Baltimare Council members and a few Governor-Mayors).
Sometimes, the local Baltimare government would proclaim royal decrees null and void within it's borders.
On one particular occasion, 125 years before the return of Princess Luna, Baltimare declared it's independence from Equestria, and Celestia was forced to send in the Royal guards to force the local regime to rescind it's declaration of independence.
Now, a local pro-independence party has elected a majority in the Baltimare Council and it's leader, a Pegasus pony who happens to be a cousin of Rainbow Dash, was elected Governor-Mayor.
The Mane Six, led by Princess Twilight Sparkle, is sent to Baltimare to persuade the local government not to break away from Equestria.
Meanwhile, Prince Shining Armor, in preparing to invade Baltimare with a legion of Royal guards should peaceful negotiations fail.