Vasily Klyuchevsky’s A Course of Russian History (1902-04) was translated into English by C. J. Hogarth and published in 1911-31. All the five volumes can be found at archive.org by searching for Kluchevsky, without the first y. Judging by Volume I, Hogarth did not merely translate the Russian text but modified it by abridging and re-chaptering. Lectures 2-4, where Klyuchevsky speaks of “colonization as the principal fact of Russian history” and discusses the country’s geography as a historical factor, are missing from Hogarth’s English version. Thankfully, this key thesis made it into Hogarth’s translation:
Thus we see that the principal fundamental factor in Russian history has been migration or colonization, and that all other factors have been more or less inseparably connected herewith.
Klyuchevsky saw four major periods of migration based on the target area: the Dnieper (corresponding to Kievan Rus’), Upper Volga (early Muscovy), Greater Russia (the Moscow state), and the whole of Russia (the Empire).
Fast forward to the second half of the 20th century. In Russia in the Modern World: A New Geography (1999), Denis J. B. Shaw suggested a more detailed classification of the regions corresponding to the stages of migration and settlement that enabled Russia’s expansion in Eurasia. To this end, the British historical geographer modified the classification proposed by Donald W. Meinig, the prominent American geographer, in The Macrogeography of Western Imperialism (1968). In Shaw’s words,
Meinig classified Western imperialism into several types, depending upon the different kinds of settlement and economic exploitation experienced in different regions… appropriately modified, it is helpful in dividing the Russian settlement experience into a series of separate types, corresponding to different regions of the former empire.
Shaw appears to take Klyuchevsky’s Upper Volga stage as his point of departure. The first region, accordingly, is the Russian (or Greater Russian) heartland, which isn’t straightforward to define – it, too, was a product of Slavic colonization – but can be visualized as the Moscow principality around 1500 without Novgorod’s northern lands and the black-earth steppes in the south, nominally claimed but very imperfectly controlled. Roughly speaking, “from Smolensk in the west to Nizhniy Novgorod in the east, and from Vologda and Velikiy Ustyug in the north to Tula in the south.”
The Ukrainian and Belarusian heartlands (“Belarus’ and the northern and central parts of Ukraine”) make up the second region.
The third region, according to Shaw,
…corresponds with what Meinig calls a “boreal riverine empire.” This territory consists of the greater part of north European Russia falling within the boreal forest and tundra vegetational zones, and also most of Siberia and the Far East, apart from the very south…
It is the fourth region that is central to the history of Novorossiya. Following Meining, Shaw refers to it as the “settler empire”…
…by analogy with the white settlement of parts of the United States, Canada, Australia and other territories. Here the basic motive for expansion was permanent agricultural settlement rather than trade… [T]he greatest impact made by Russian agricultural settlement (outside the “homeland”) was across the southerly forest-steppe and steppe lands of the European territory (including southern Ukraine) and southern Siberia. It was also important in the mixed forests of the southern part of the Far East.
Regarding the ethnic composition of these agricultural settlers and the timing of this enormous expansion, Shaw explains:
These regions were largely settled by the Russians (and also to some degree by Ukrainians, Belarusians and some other groups) between the sixteenth and nineteenth centuries.
“To some degree by Ukrainians” needs qualifying when it comes to what is now southern Ukraine, for it was quite a large degree there. Shaw makes this point clearer in this passage (emphasis mine):
As a rule, white settlement in the settler empire had a mixed ethnic character, although the Russians usually predominated. The major exception was the steppenlands of southern Ukraine, where Ukrainians played the principal part. Even here, though, many Russians also settled and their numbers were swelled from the nineteenth century by migrants moving to take up jobs in the burgeoning industries of the Donbass coalfield and the Ukrainian south.
This would be a perfect brief introduction to the historical demography of Novorossiya (in the narrow sense) if it also covered the ethnolinguistic urban-rural divide in that region, which predated its industrialization.
Ukrainians also made up a large part, possibly the majority of early agricultural settlers (1883-1914) in the “southern part of the [Russian] Far East.” Those who followed the regional elections in the Primorsky (Maritime) krai in September-December 2008 might have noticed that most of the candidates bore Ukrainian or South Russian names.
Finally, the fifth domain, corresponding to Meinig’s “nationalistic empire,” wasn’t much about settlement as it “embraced territories peripheral to Russia proper,” including
…the former Baltic provinces (now the three Baltic states of Estonia, Latvia and Lithuania), the Transcaucasus (the states of Georgia, Armenia and Azerbaijan), parts of the North Caucasus now within the Russian Federation, most of Kazakhstan (with the probable exception of the north where there is much Russian settlement) and the four states of Central Asia…
Prof. Shaw’s book also has helpful maps outlining the five regions. The book can be borrowed from archive.org.