The Scots Gaelic clan seal was inscribed, "S' Riogal Mo Dhream/ Een dhn bait spair nocht", which was interpreted as "Royalty is my race / End do and spare not".

[3] Since 1837, MacGregor had been operating a ferry across the Mississippi River between Prairie du Chien, Wisconsin and the present site of McGregor, Iowa.

MacGregor planned the new city as a six block development, and it was quickly populated, being incorporated as McGregor in 1857.

In that same year, the Milwaukee & Mississippi Railroad finished building a railroad track from Milwaukee, Wisconsin to Prairie du Chien, Wisconsin, thus connecting Lake Michigan with the Mississippi River by rail.

McGregor quickly became a major commercial center, and served as a hub where grain from Iowa and Minnesota could be transported across the Mississippi and sent on to Milwaukee via railroad.

For example, around 1860, Joseph "Diamond Jo" Reynolds moved to McGregor in order to establish a grain trading business, and later ran his own steam packets.

After reaching McGregor from the west, trains were disassembled and railroad cars were ferried across the Mississippi to continue on towards Lake Michigan.

The towns early residents made use of the bedrock to carve cellars into the soft sandstone, used for cold storage and ageing beer; as of 1997 most of the entryways are visible but inaccessible.

[5] In 1874, the system of ferrying railroad cars across the river between North McGregor and Prairie du Chien, Wisconsin, was brought to an end when Prairie du Chien businessman John Lawler commissioned the construction of a permanent pontoon bridge to connect the two cities' rail lines.

As the need for men to disassemble and ship trains across the river disappeared, the city's population began to decline.

Because of its colorful history and location beside the Mississippi River, the city has become a popular summer tourist destination, and it is known for its many antique stores.

The city was heavily damaged during a storm on July 19, 2017, with the downtown area being particularly hard hit.

[5] According to the United States Census Bureau, the city has a total area of 1.30 square miles (3.37 km2), all land.