A look at Canada:

Study: A comparison of urban and rural crime rates

Of the 658 homicides in Canada in 2005 with a known location, 427 were committed in large urban areas, 95 in small urban areas and 135 in rural areas.

Taking population into account, the homicide rate of 2.5 homicides per 100,000 people in rural areas was actually higher than the rate of 2.0 in large urban areas and the rate of 1.7 in small urban areas. This pattern has held constant over the past decade.

However, robbery and motor vehicle theft were much more likely to occur in big cities than in small cities or rural areas. The robbery rate for large urban areas was more than double that for small urban areas and almost 10 times that for rural areas. The motor vehicle theft rate in large urban areas was about 25% higher than in small urban areas and 80% higher than in rural areas.
If you read the bit about the laws of small numbers and keep in mind the differences in (medical) infrastructure between the larger urban areas compared to say rural areas then you will be quite careful at reading too much into this result as well. It is much safer from a statistical point of view to work with (much) larger samples. So it is important to be sceptical when faced with this kind of graphs - without going too far into the other extreme.

Handguns are the firearm of choice in big-city homicides

In 2005, just over one-third of all homicides in both large urban areas and rural areas were committed with a firearm, compared with less than one-quarter of homicides in small urban areas.

Handguns were the weapon of choice in large urban areas, used in 76% of all firearm homicides. In rural areas, rifles or shotguns were the most prevalent; they were used in 65% of firearm homicides.

Weapons more common in large urban areas in Quebec and Ontario

In Quebec and Ontario, the only provinces where data on weapon use in violent crimes were available for both urban and rural areas, about 1 in 6 violent incidents involved a weapon of some sort, most commonly a knife.

Weapons were present more frequently in large urban areas than in small urban areas and rural areas of these two provinces. About 1 in 5 violent incidents in large urban areas involved a weapon, compared with about 1 in 8 in small urban areas and rural areas.

The proportion of violent crimes involving a firearm was about two to three times higher in large urban areas. In 2005, 3.2% of violent crimes in the large urban areas of Quebec and Ontario involved a firearm, compared to 1.1% in small urban areas and 1.4% in rural areas.

When a firearm was present, handguns were more prevalent in large urban areas than in the other areas. Handguns were used in three-quarters of crimes committed with a firearm in big cities compared to about half in small cities and one-third in rural areas.
The difference between the use of firearms in homicides between Canada and the US is very considerable indeed. Firearms account for the clear majority of US homicides, while in Candada it is roughly a third. Rifles and shotguns seemed to used much more in relative terms in rural Canada compared to the US but we need more data on that.

Note to readers

Large urban areas are defined as Census Metropolitan Areas (CMAs). A CMA represents one or more adjacent municipalities centered on an urban core of at least 100,000 persons. Based on police boundaries, large urban areas accounted for 65.5% of the Canadian population in 2005.

Small urban areas are defined as any urban area not part of a CMA that has a minimum population of 1,000 persons and a population density of at least 400 persons per square kilometer. Small urban areas accounted for 17.4% of the population in 2005.

Rural areas are defined as all areas of the country not falling into either the large urban or small urban categories. In 2005, rural areas accounted for 17.1% of the population.
All in all it is remarkable how little violence is done by so many humans with so many weapons. The drop in homicides in larger cities, especially those over a 1,000,000 is highly interesting and IIRC another topic discussed it already. NYC and Los Angeles account of course for a majority of the population of those 9 cities with the effectivness of it's policies having a massive impact on the aggregate.