IQueryable returns 3693 items but inserts 1000 to dropdown

Question

Hi all,
I am querying SharePoint to retrieve all the lists of accounts. I can see that I have 3693 account items when I query the results. However when I convert this into a lists or insert this as DataSource of a dropdown field, it only takes the first 1000 items of the results. 

Code preview
...
var organisations = from d ....... ; 
Debug.WriteLine("Results returned.. " + organisations.Count());//3693
Debug.WriteLine("Results converted to Lists " + organisations.ToList().Count()); //1000
dropdown.DataSource = organisations; OR dropdown.DataSource = organisations.ToList();
//only displays the first 1000
... code continues

Am I inserting the data wrong? Help!

Regards,
Roldan