Getting an object inside of list of list

If you just want a specific one of the inner List<MyObj> then use the indexer

List<MyObj> local = list[0];

If you want all of the inner lists viewed as a single List<MyObj> with the inner ones just being combined together then use SelectMany

List<MyObj> local = list.SelectMany(x => x).ToList();

List inner = outerlist[indexOfListYouWant]

A list inside a list can be accessed just like any other object in that list.

You need only iterate over the outer list like so:

foreach(List<MyObj> innerList in list)
{
    // do stuff to innerList
}

Which is the "inner lists" do you want?

 List<List<MyObj>> list;
 List<MyObj> MyObjList = list[0];

To access one (here, the first) of the many inner lists:

List<MyObj> inner = list[0];

To turn this "jagged" 2-dimensional list into a single one-dimensional list:

List<MyObj> oneList = list.Aggregate(new List<MyObj>(), (inner, result) => result.Concat(inner)).ToList();