Thanks a lot for your replies and explanation on how Congressional Districts are created!....esp jimrtex's summarize of it all.
It is very simmilar to the way we in the UK create 'constituencies' to elect our 659 MPs with approx 69,500 population in each, but they do not split 'Counties' over here tho.
The systems are similar if you consider counties in England and Wales as equivalent to States in the United States. In England and Wales, a number of constituencies is apportioned to each county, in the US a number of representatives (and districts) is apportioned to each State. In the US, the apportionment is strictly mathematical.
Note: I am deliberately making a distinction between England and Wales, and Scotland and Northern Ireland because the procedures for defining constituencies are somewhat different.
In England and Wales, some consideration is given to how many "natural" constituencies a county may be divided into, as well as maintaining historical continuity. A county that was entitled to 4.3 MPs might have 5 MPs if the county more naturally can be divided into 5 roughly equal constituencies, especially if it has had 5 in the past. And this can work in the other direction, where a county that is entitled to 4.6 MPs might only have 4.
In addition, in England and Wales, county boundaries may be breached. In the US, it would be impossible to cross a State boundary, even in extreme cases like Montana and Wyoming.
Within, English counties and within US States the process is somewhat similar. In England, some deference is given to district council boundaries, in the US, States often give some deference to county boundaries. In the US, court decisions have generally resulted in districts being extremely equal in population.
The process may be different for State legislative districts. In Texas, counties entitled to more than one representative must have a whole number of districts, plus possibly one remnant that is combined with adjacent counties or remnants of other large counties. Smaller counties may not be split. For example if you had one county with a population of 1.6 districts, and and an adjacent county with 1.4 districts, there might be one district in each of the counties, and a cross-boundary district between the two counties. Alternatively, the county with 1.6 districts might be placed with a smaller county or counties entitled to 0.4 districts. One district would be entirely in larger county, with another district formed with the remainder of larger county and the smaller county(ies). The US Supreme Court has accepted somewhat greater variation in the population between legislative districts. In Texas, it is assumed that a 10% difference will be accepted. In a few exceptional cases, this has resulted in a district or two that is not strictly in compliance with the Texas Constitution (but is in compliance with the USSC interpretation of the US Constitution).