How are blood clots treated?

Clot treatment gets asked about as if every clot were handled alike, and readers around Tinley Park often have a leg clot and a lung clot in mind at once. This page gives the general statement first and points to the pages where each case is set beside its look-alike.
The general answer
medlineplus.gov puts the starting point this way: Treatments for blood clots depend on where the blood clot is located and how severe it is.
Where the leg and lung questions part ways
Because the answer turns on location, this site keeps a separate page on how DVT is treated. Cleveland Clinic's deep vein thrombosis page is the leg-side source to read first.
A second institution's account
The NHLBI page on venous thromboembolism treatment comes from an NIH institute and reads best as its own account, set beside the one above.
The follow-up question
The source ties treatment to location and severity, so the natural next question is how doctors find out where a clot is.