Drive anywhere in Maine, you’ll most likely cross a bridge.  Due to Maine’s Coast, Lakes, Rivers, Railways and gulches, a bridge is helpful to transport you and your family out of harms way.  There are numerous bridges in Maine, all kinds, from covered bridges, big spanners, short rock bridges, and granite bridges like the one connected to Orrs Island.

The Penobscot Bridge site also is home to the Penobscot Narrows Observatory, the first bridge observation tower in the United States and the tallest public bridge observatory in the world. The tower reaches 420 feet (128 m) into the air and allows visitors to view the bridge, the nearby Fort Knox State Historic Site and the Penobscot River and Bay. The tower is accessible through the Fort Knox site and as of August 2009 charges a $7 fee for adults which includes admission to both the Observatory and the Fort Knox site.
The Penobscot Narrows Observatory opened to the general public on Saturday, May 19, 2007 and remained open until October 31. It is open at the same times of the year as Fort Knox (May 1 to October 31).

The Penobscot Bridge site also is home to the Penobscot Narrows Observatory, the first bridge observation tower in the United States and the tallest public bridge observatory in the world. The tower reaches 420 feet (128 m) into the air and allows visitors to view the bridge, the nearby Fort Knox State Historic Site and the Penobscot River and Bay. The tower is accessible through the Fort Knox site and as of August 2009 charges a $7 fee for adults which includes admission to both the Observatory and the Fort Knox site.
The Penobscot Narrows Observatory opened to the general public on Saturday, May 19, 2007 and remained open until October 31. It is open at the same times of the year as Fort Knox (May 1 to October 31).

Piscataqua River Bridge

The Piscataqua River Bridge, is a cantilevered through arch bridge that crosses the Piscataqua River, connecting Portsmouth, New Hampshire with Kittery, Maine.

The Ticonic Footbridge, usually called the Two Cent Bridge, is a suspension bridge that traverses the Kennebec River between the cities of Waterville and Winslow in Maine. It is one of the oldest surviving wire-cable steel suspension bridges and also is considered to be the last known extant toll footbridge in the United States.

The Waldo-Hancock Bridge was the first long-span suspension bridge erected in Maine, as well as the first permanent bridge across the Penobscot River below Bangor. The name comes from connecting Waldo and Hancock counties. The bridge was retired in 2006 as the new Penobscot Narrows Bridge was opened just a few yards away.

Waldo Hancock Bridge

New Portland Wire Bridge

Good story on Remaining Covered Bridges in Maine by Portland PressHerald:

click here