If I overstay my visa in USA are they going to search for me?

You need to understand that you are removable if you overstay your visa. This means that the Government can place you into removal proceedings. Further, if you overstay by more than six months, you will be subject to a three year bar of reentry. If you overstay for more than one year, you will be subject to a ten-year bar of reentry. Depending on the type of visa that you have, you may be able to apply for an extension.

All right...Normally, a tourist status is issued for 6months for most people who travel to the US with a visa, or 90 days for people from certain country who do not need a visa to enter. If you come in for 6 months with a visa: You can file an extension, but the reason must be good and it must be documented. This might keep you in legal status. If you come in with no visa, just the passport and are admitted for 90 days: you can not get an extension or a change of status. If you do not file / get an extension, you become an illegal alien. This doesn't mean that ICE will look for you...but if you end up in jail for any reasons, ICE will come and visit and ascertain your status. People in some crazy areas like AZ have ended up in their home country for something as simple as jaywalking. You simply can be at the wrong place at the wrong time: A client of mine got taken by ICE when ICE showed up at his door: ICE was not looking for my client but for the prior occupant who had an arrest warrant...This means you have to be extremely careful at all time. Finally, even assuming you do not get caught while being illegally in the US, there is another complication: The CBP keep tracks of in-and-outs. One day, they will find out you overstayed by either more than 6 month but less than one year, and will ban you from returning to the US for a 3 year period. I really suggest NOT to overstay your authorized stay.