The Monarch was a 63 foot, 49 ton tugboat that sunk in the St Clair River just South of the Blue Water Bridge in Port Huron, Michigan in July of 1934. It was towing another ship upriver when the ship got caught in the current and pulled the Monarch over on its beam. Her stern was pulled underwater which allowed water to enter her hold. In sinking she took four of her eight man crew with her. 

To get to the site take Interstate 94 East to Port Huron and cross over into Canada. To be on the safe side take some form of identification such as a birth certificate or voter registration to prove citizenship. It is not usually needed but it is better to be safe rather than sorry. Once you exit the bridge take the first right and then a right again. Take this road to the river and then make a left. There  will be a blue building on your right. Park just to the left of this building. At the rivers edge you will find a set of steel stairs that lead down to the water. You can use these stairs or enter to the left of the cement pier in shallow water. 

The monarch is relatively intact, lying in 60 feet of water. To find the wreck enter the water either using the stairs or entering to the left in the shallows and swim to the pilings between the two. Submerge here and gradually descend to the submerged retaining wall. Here you will find a cable. This cable will lead you gradually to the wreck. In the shallow area near shore there will be relatively light current so it is usually not necessary to hold onto the cable. Remember this is a steel cable and can cut a pair of gloves. As you descend the current will pick up and within 15 to 20 feet of the wreck will usually be quite strong, enough that holding onto the cable will be a necessity. The wreck points into the current and the deck side offers protection from the current. You want to remember that the current often surges here and at times seems quite slow and then can become quite strong. On the wreck you can explore the bow, the wheelhouse area with head, the engine area, and hold. The visibility on this wreck is usually quite good for the St. Clair River, averaging 10 to 20 feet. To exit from the wreck just follow the cable back to shore. 
Besides the wreck there are interesting fish in the area and look for the mud puppies. 

 Remember since the current can vary and is usually fairly strong on the wreck this wreck is recommended for experienced divers. I would rate this wreck an upper intermediate to advanced dive. If for any reason you are blown off the wreck don’t panic, just swim along the sandy bottom back in direction of shore (Canadian, the US shore is along way off). Also remember during the summer months there is a lot of boat traffic, so surface near shore