“There is also no definite explanation for why northern New England tends to have a lower violent crime rate than other regions, although evidence points to several factors.”
It would be an interesting project to write a book on the varying regions of the United States and their violent crime and homicide rates, tied to the firearms laws and culture of firearms ownership. I would have a section on Northern New England (NH, VT, and ME) about it’s relatively casual laws accompanied by low violence rates.
Also the Atlantic area (MA, NY, RI, MD, DE, NJ, and DC) with it’s generally stricter laws accompanied by higher crime and violence rates. The Old South would include VA, WV, FL, GA, AL, MO, MS, LA, NC, SC, TN, MS, and AR. I would write a separate chapter on Texas as it started out as basically an independent country with it’s own unique culture of firearms ownership and laws. The Old West would include PA, KY, OH, MI, IL, IA, MN, WI, and IN. The New West would highlight NB, the Dakotas, MT, ID, NV, and AZ. And finally the Pacific would be about CA, OR, WA, HI, and AK.
You could discuss when these areas were settled and populated by what cultures and races primarily and degree of urbanization, etc and how crime rates and firearms laws and ownership culture were uniquely tied to all of this.
In Maine, we have an aged population too.