Well actually its not hard to imagine. Think about earth in the middle ages, a lot of areas in Europe stagnated and the population declined due to wars, famine, disease etc. In the bttletech universe its no different. The Amaris Coup and the following war was a massive battle, in which a lot of lives, eaponry, infrastructure factories, jumpship, etc were destroyed. After the war, efforts would have then focuses on rebuilding, in a way focusing inwazrd and worrying about what ' you' have already and fixing that. Then following the next three centuries of war which included 4 succession wars. Nuclear, biological, scroched earth policies were used, with many Star league facilities, technology, factories infrastructure, were again destroyed. Massive amounts of money were again poured into 'what we have' to protect it. The war machines of the Houses absorbed the money of the nations, and i would expect that exploration and colonisation was cut as it would be a fairly expensive undertaking to increace their military power.

You also have to remember that the 300 hundred years where the IS was settled was acheived under a single central authority, the Terran Hegemony and in a period that was a golden age, with minimal war.

Remeber also that exploration still did occur. The Comstar Explorer Corp was established and they explored and found the Clan Homeworlds. Further, individuals formed Periphery worlds and bandit kingdoms. The Mariam Hegemony, etc are examples. Also a lot of 'private settlers have moeved into the periphery. You have to remember that a lot of the pertiphery is not under the control of Houses and are more individual planets and as such arent shown on the IS map.

The total region inhabited by humans is actually a bit hazy even in 3133.

They still occasionally find long-dead colony worlds from the first great exodus from Earth, and ever so rarely they find a working colony world from those days, some of them have degraded back to what we were in the 1950's or even earlier.
That and it seems that the expansion was mainly hobbled by the generally inefficient KF Drive in use currently.

It seems that the original Jumpships (before SL) were more like a Warship. They apparently had no sails, used a massive engine block and fusion reactors to charge the batteries and were more similar to a high-performance WarShip than anything else.

This is basically true. They were really more like a low-performance WarShip; IIRC the compact core which separates combat JumpShips from transports came about fairly late in the game, after the jumpsail. Much, but not all, of the main wave of colonizations (2200s-2300s) occurred without the jumpsail, yes.

Last of all of the major players was the modern DropShip, actually. That was really what allowed BT JumpShips to discard their maneuver drives and get by with the much smaller stationkeeping ones they use in 3134; before that they had to burn in-system and offload with planetary shuttles and other small craft.

We all have to remember that while there are billions of other planets, very few could possibly support human life. Most stars only have one or two planets orbiting them, some of which are too close to that sun to inhabit, or too far away to acommidate anything other than an observtion post which in most cases, is a waste of recources.

But, since the Clans have returned, and with them came many of the old Star League era warships and numerous new designs (most likely w/ slightly more advanced drive systems, after all, the wars between the Clans weren't nearly as bad as the succesion wars, so more time/resources could be spent on science) exploration might possibly make a come back in the storyline's future. Especially if many more planets are rendered uninhabitable from chemical, nuclear, biological warfare, etc.

Lots and lots and lots and lots of war, Killing off enough people so that their is no need to expand, Keep in mind that most Planets that are Habitable are not Even anyware as near as crouded as earth is now, Most only have Hundrends of millions, Or 1-2 Billion, So if the earth as it is now supports 3.5-4 billion people being a Realtivly small planet, I would think that with consorvation of resources they would not need to expand much. Anyways, why would the IS want to deal with the periphy Bums O_o

The reason for the stop is simple....after the Great war was over Kerensky took almost all of the space ship's (warsips and Jumpships) with him when he left to go form the clans.....Nuf Said.

Whole it may take massive amounts of Money as well as Time to rebiuld Jumpships...i think it could be done, Also how many people died in the Jihad? Ill bet its enough to set the population back a Generation or 2 O_o Still Sooner or later their will be expancion just not yet.

I missed an important point in my analysis, and one that needs to be discussed.

Taking a look at the American West, it was EXPLORED long before it was SETTLED. Lewis and Clark explored the Missouri River and the Pacific Northwest in the early 1800s. Fur trappers and miners, scouts and explorers were in the area for a half a century. But it took the massive influx of new immigrants mmeting up with the devastation of the Civil War to prompt large-scale migration and settlement in the West. Most of the "Wild West" legends were set in the 1870s-1890s, almost 100 years after that territory officially became part of the United States. It wasn't until the advent of the railroads began to link these communities that growth really began to increase. There was a large gap betweeen first discovery and settlement (with sufficient population and infrastructure).

That is most likely the case here. The periphery of unsettled space is vast, and there may be a few exploratory missions looking for germanium and other valuable metals (like the fur trappers and scouts of the 1800s), and a few trading posts here and there set up to support them (like fort Bridger, etc.). But there is insufficient large scale resettlement yet, because goods and services needed cannot be sufficiently efficiently moved to sustain them.

It hasn't quit growing...just remember that a few of the Periphery States are still extending their reach outwards...

...also, just as always, you must remember that the remnants of Clan Wolverine have yet to be found! They have had over three centuries to cut out a nice little hidden collection of plantes as well.

Also...don't forget the Clan "Homeworlds", there is a lot of indication that the clans of the innersphere have been cut off from them...unknown why at this time...but the "Warden" clans left behind could be extending their power base as well.

A portion of the WoB also got away as well...this could be very bad!

And again...I have to return to the speculations of Devlin Stone...no one knows where he came from, where he learned to fight, etc... His life before the WoB reeducation camp is a blank to the players...we'll see!

These things will spell the next "crisis" for the innersphere...as they decimate each other while they allow the Periphery, Homeworld Clans, and those "missing" anomolies grow stronger beyond the innersphere's reach.

Thank you for selling out the possible location of the Not-named Clan to me.

Ghost Bears, unite! :P

Selling out?

How do you know that we don't WANT you to know where we are?

Hint, hint, wink, wink, nudge, nudge...

Another thing that is worth looking at is the short history of the Fronc Reaches.

In the late 3050s / early 3060s, the Taurian Concordat and Magistracy of Canopus formed an alliance for the primary purpose of colonizing the space between them, which was first called the "New Colony Region."

The Canopians and Taurians dumped a lot of resources into forming the "Colonial Marshals," who were constantly attacked by pirates, bandits, and outlaws. Then the administrator of the region, backed by some of the Colonial Marshals, declared its independence and took Taurian Protector Jeffrey Calderon hostage, and Calderon died during the hostage rescue, ultimately leading to the breakup of the Concordat. Then, later on, the region did declare its independence as the "Fronc Reaches" and was recognized by the Magistracy and Concordat, but Sun-Tzu Liao parked the commander of the Death Commandos in their capital city to make they didn't stir up any "trouble."

After all that is it any wonder there's not much enthusiasm for organized colonization in the Periphery? :P

Even more stuff to consider...

Just because the planets outside the standard Inner Sphere aren't usually mapped, doesn't mean they don't exist or aren't colonized.

http://www.netbattletech.com/nbt4/maps/3063.pdf

BT makes numerous references to influxes of colonization in the Periphery during/after every major upheaval in the IS. (See, for example, the Rim Collection) So clearly there is continued growth of colonization of some sort. However, piracy is a major issue and a significant hindrance to colonization (e.g. the Colonial Marshals were overstretched).
What's more, the Houses may not have much need for continued colonization. The need for colonization can only arise from 2 factors: need for additional natural resources and need to deal with "excess" population. It is entirely possible that the costs of colonization to gain new resources are too high (protection of the colony from piracy by an already overstretched military could prove a significant obstacle). Moreover, there may not be that much population pressure either. Assuming populations continue to expand (the Earth's population will cease expanding sometime late in the 21st century if current trends hold), there is still lots of space on a planet and lots of planets in each realm. The Davion periphery, for example, is sparsely settled and largely underdevleoped.