S. Sudan is 3.3 times larger than Senegal.
Area: 644,329 km2 World Factbook
Population: 11,562,695 (July 2014) World Factbook
South Sudan, officially the Republic of South Sudan, is a landlocked country in northeastern Africa that gained its independence from Sudan in 2011. Its current capital is Juba, which is also its largest city. Wikipedia
Area: 196,722 km2 World Factbook
Population: 13,635,927 (July 2014) World Factbook
Senegal, officially the Republic of Senegal, is a country in West Africa. It is the westernmost country in the mainland of the Old World or Eurafrasia and owes its name to the Sénégal River that borders it to the east and north. Wikipedia