Looking for long lost family - family name HALAJ

Hello all,

I and my family we just started a search after my long lost great-grandfather who emigrated to Buenos Aires sometimes after 1924/1925. We don't know the exact date, but trying to find more information on that.
The only information we have at the moment from the letter he wrote back in September 1947 are two cities mentioned on the top of the letter - Arroyo and Avellaneda. I know those cities are miles and miles apart, but that's all we have.

I was wondering if anyone on here knows where to start our search apart from obvious websites such as geni.com and myheritage.com Are there any websites with an online archives or organisations for Czech/Slovak expatriates that might help our search?
My great-grandfather was born in Badin, a small village close to Banska Bystrica/Slovakia. He was born in 1897. It would be great if we will be able to find any information that might lead to find any new family he might after moving to Argentina. Many thanks in advance!!

Have a great day all!!

Hi Good day

1.You could start of through Facebook making contact with people that share the same surname in Argentina.

2. You might not find any info online. Due to Argentina law in the past any immigrant that immigrated to the country had to possess a Spanish surname. So most probably your great grandfather had to change his surname. But the government does have a record of all immigrants with their original surnames. You will just have to contact them and hopefully they would be able to provide you with what you looking for

Good luck