The city with the most murders in the United States varies from year to year, but some of the cities that have consistently ranked high in terms of murder rates include Baltimore, MD; New Orleans, LA; Detroit, MI; St. Louis, MO; and Memphis, TN. Factors that influence crime rates in these cities include lower arrest probabilities, social influences, and family structures. Crime rates in metropolitan statistical areas tend to be above the national average, and many attribute the high violent crime rates to gangs and gang violence in urban areas. Its important to note that the murder rate of a city is calculated as the number of murders per 100,000 people, so its not solely based on the total number of murders.