The Harappan civilization, also known as the Indus Valley civilization, thrived between 2600 BCE and 1900 BCE in the northwest regions of the Indian subcontinent. Although there is limited evidence of direct contact with other contemporary civilizations, there are several indications that the Harappan people had interactions and trade relations with other countries of that time.

Evidence of Trade:
The presence of certain artifacts and materials found in Harappan sites suggests trade connections with other regions. These include:

1. Seals: The discovery of Harappan seals in Mesopotamian cities such as Ur and Susa indicates the existence of trade networks. These seals, made of materials like steatite, were used for stamping goods and containers, and their presence in Mesopotamia suggests a level of interaction between the Harappans and the people of these regions.

2. Imported Goods: Excavations at Harappan sites have revealed the presence of materials not found locally. For example, lapis lazuli, a blue stone used in jewelry, was not available in the Indus Valley but was found in abundance in regions like Afghanistan. This suggests that the Harappans engaged in long-distance trade to acquire such materials.

3. Standardized Weights and Measures: The use of standardized weights and measures across Harappan sites indicates the need for consistent trade practices. This suggests that the Harappans engaged in trade with distant regions, as standardized systems would be necessary for fair transactions.

Urban Planning and Infrastructure:
The well-planned layout and sophisticated infrastructure of Harappan cities indicate that they were centers of economic activity and trade. Key features include:

1. Grid-like City Layout: Harappan cities, such as Mohenjo-daro and Harappa, had a well-organized grid-like layout, with streets, houses, and public buildings planned in a systematic manner. This indicates the presence of a centralized authority and economic activities that required efficient management.

2. Advanced Drainage Systems: The sophisticated drainage systems found in Harappan cities, including covered drains and public baths, suggest a high level of urban planning and infrastructure development. Such infrastructure is often associated with prosperous trading cities.

The Extent of the Harappan Civilization:
The vast geographical distribution of Harappan sites also implies their connections with other regions:

1. Trade Routes: The presence of Harappan sites along major rivers, such as the Indus and its tributaries, suggests that these rivers served as trade routes connecting the civilization with other regions. Goods and ideas could have been exchanged along these routes.

2. Coastal Connections: The discovery of Harappan sites in coastal areas, such as Lothal, indicates their involvement in maritime trade. These coastal settlements would have facilitated trade with regions across the Arabian Sea and the Persian Gulf.

While direct written records from the Harappan civilization are yet to be deciphered, the evidence mentioned above supports the idea that the Harappan people had trade and cultural interactions with other countries and regions of their time. The presence of seals, imported goods, standardized measures, well-planned cities, and extensive geographical distribution all point towards their engagement in trade and connections with other civilizations.