My first thought was Pennsylvania, as they have an interesting and varied climate, rivers, mountains, and plenty of historical mineral resources.
However, after a bit of searching, I found this interesting gem:
In the decades after the Civil War, Alabama became one of the nation's leading iron and steel producers. Although Gadsden and the Florence Sheffield District along the Tennessee River contributed to this rise, the Birmingham District became the largest iron and steel producer in the southern United States. Unique geological conditions provided the district with closely associated and abundant deposits of iron ore, coal, limestone, and dolomite. These were the raw materials essential for making iron and steel, and at some locations within the district, deposits were only a few miles apart. This lucky geological arrangement resulted in the lowest raw-material assembly costs in the United States...
The close juxtaposition of their raw materials allowed iron makers in the Birmingham District to create companies that were industry models of what is known as vertical integration. Most of the Woodward Iron Company's holdings, for example, were linked by a remarkably short, 12-mile railroad. The company-owned track extended outward from its blast furnaces and coke ovens, to its limestone and dolomite quarries, to its ore mines on Red Mountain and its coal mines along the edge of the Warrior coal field.
(from
Iron and Steel Production in Birmingham)
The vast deposits of iron ore, limestone and coal, all in close proximity, in the Birmingham area of Alabama have placed this area in a dominant position in the iron and steel industry in this country. In no other State are these essential raw materials found within a radius of five miles of each other. The economy of production under such conditions is obvious.
The total supply of iron ore in this district is believed to he adequate for 150 years, as compared with an estimated supply of only 35 years for the rest of the country, based on present rate of consumption.
(from
a 1940 Georgia Tech article)
Given that iron ore, limestone (flux), and coal are in close proximity (closest in the US and possibly the world), along with some nice hills / small mountains and rivers, sounds like what DF players would search for in earlier versions; the
Birmingham, AL, USA area seems to be ideal.
Now, in recent versions, magma access is more or less guaranteed; so plentiful coal resources are less critical. It might be interesting to look for areas with other mixes.
For instance, the modern vicinity of
Magdalensberg, Carinthia, Austria area was part of "Noricum", a Celtic kingdom closely allied with Rome, and later a province. The area was known for superior sword steel for at least half a millennium, as the iron ore was high-manganese, low-phosphorous, both characteristics being critical to low-tech carburizing of iron into superior steel. The area also has (or had) plentiful gold, salt, lavender, and lumber.