Where was America and other countries when Ramayana and Mahabharata were happening in India?

 

These were explained well in puranas.

America is in Krauncha Dweepa. This Krauncha Dweepam (an island with area of 16 lakhs into 12 miles) is beyond Ghrutha Samudram (Ghee ocean). There is Ksheera Samudram (milk ocean, with area of the same 16 lakhs into 12 miles) beyond this island. Krauncha Dweepam (Island) contains seven mountains as it's boundaries. Seven rivers are running through these mountains. The Krauncha mountain has been cut by Lord Subrahmanyam to reduce its arrogance, on the request of all Gods.

Kuruvarsham (a continent) is north boundary to Jambudweepam (Asia). Russia is in Kuruvarsham and it's old name is Kirikisthhan. Arjuna conquered Uththara Kuru Lands. Thushara Rajyam had become Thurkamenisthhan and Kambhoja rajyam had become Thazikisthan.

There was a large forest in Krauncha Dweepam, and its name is Kapilaranya. This forest has become now, as California.The earth was divided into seven islands after the ruling of the sons of Swayambhuva Manu, who ruled the earth before six Manvantharas. Jambudweepam, Krauncha Dweepam, Plaksha Dweepam, Shalmali Dweepam, Shuka Dweepam, Shaaka dweepam, and Pushkara Dweepam are the seven ones. Now, the seventh Manvanthara is running. (One Manvanthara is equal to 71 mahayugas, i.e., 30,97,20,000 years, such many Vedic calculations were solved by Daevis, Max Muller like western scholars very patiently. See more for other calculations of time cycle in Google, Vedas or Puranas.)

Priyavratha, the first son of Swaayambhuva Manu, ruled the earth for 60 lakhs years. (The younger brother of Priyavratha was Uththana pada. Uththanapada was father of Dhruva, the pole star). He divided this earth for his seven sons.

Jambudweepam was given to the King Agneedhra by Priyavratha Chakravarthy. The another island, Plakshadweepam was ruled by Medhaathithhi. Shalmali Dweepam, Kushadweepam, Shaaka Dweepam, Krauncha Dweepam, Pushkara Dweepam (the other islands) were ruled by Vapushmantha, Jyothishmantha, Dyuthimantha, Havya, Savana Kings respectively. Meru mountain is middle to this Jambudweepam. The Sun circles this mountain. Salt ocean (Lavana Samudram) is around this island. Agnidhra divided again the Jambudweepam as nine parts and gave them to his nine great sons. These lands were called by their names as Nabhi, Kimpurusha, Harivarsha, Ilavrutha, Ramya, Hirannvantha, Kuruvu, Bhadraashwa, Kethumala. The son of Nabhi was the great Rushabha Chakravarthy. He had hundred sons. His first son was the king Bharatha. He ruled Nabhivarsha (a very large continent) very well. From then onwards, Nabhi Varsha became Bharathavarsha. This is all written by Vedavyasa, 5,100 years ago, and many proofs are there. These were written in Mahabharata also. 

Mahabharatha says Pandavas conquered Yavanas that is the Greeks, Romas or Romans, Sri Lanka, Bangladesh, Pakistan, Afghanistan, Nepal, China/Tibet. The mention of Turks or Iran and Middle East in General is made.

The map of Mahabharatha is Indian subcontinent and Parts of Middle East, Europe and China also. Texts say that the Mahabharatha empire spanned entire "Pangea" which was a single continent on earth and was bigger than India, Pakistan, Bangladesh, Nepal, Afghanistan, and mostly parts of Europe and China too.

When Mahabharata happened the subcontinent was called as Bharatvarsha, named after the valiant king Bharata or a somewhat smaller section of "Aryavarta" (original name) Or Jambudweepa. Hence even today, Bharat is one of the official names of India.