The Harrison is located on Goose Island in Chicago. You might be thinking how can there be an island in Chicago. It's an interesting tidbit of history as it was a man-made created island in part of the city. This is the area on Erie Street where Madeline Donovan resides. This part of the series is integral to the Donovan series as it is the home base.
The three-flat brick home her family resides in is based on the actual home of my ancestral family who lived in this home. Though they weren't the first family who owned it, it was built in 1878, and many of the buildings on this street were built at the same time. So even though it was a lifetime later, I was able to see the buildings as they existed at that time.
Chicago was rife with crime even in those days and bursting at the seams to grow into a major US city. I enjoy writing about hidden rooms and secret passageways and include them whenever I feel it's plausible and in this story, they are plentiful!