Los Antiguos is a town in Argentina on the border with Chile in Santa Cruz province. It's on the shores of the Lago Buenos Aires, which is called Lago General Carrera on the Chilean side.
East towards Perito Moreno
Walk to the out of town police control, put down your stuff, put up your thumb. All traffic goes to Perito Moreno from here.
West towards Chile Chico inside Chile
From the town's centre, it's a 3km walk to the Argentinian immigration office. Stamp out and catch a ride in no man's land, which is an 8km long looped road over a little river that drains from the lake. There you'll have Chilean immigration - which will steal all your fruits, cheese and nuts if you try to take them - and your entry stamp. Catch another ride after the border to cover the last 10km into Chile Chico. Mind of a Hitchhiker hitched this road in autumn, but in the opposite direction. She made a vlog about this border crossing.