Alajuela Province

The Costa Rica province of Alajuela is, arguably, the most diverse province in terms of geography and development. 

For example, Alajuela (the province) is home to Juan Santamaria International Airport (airport code SJO) - the busiest airport in Costa Rica - located in the city of Alajuela. Alajuela, the province, is also home to Volcan Arenal - one of the most popular tourist attractions located in the north central region of the country in the cloud forests. Whereas the international airport is simply an extension of the greater-San Jose metropolitan area, the area north of there is quite rural. 

One of Costa Rica's most active (and easy to visit) volcanos is Poas Volcano, located in Alajuela. Poas is easily visited during a day tour from locations throughout the San Jose metropolitan area.