Comprising five provinces—Cavite, Laguna, Batangas, Rizal, and Quezon (hence the acronym)—and one highly urbanized city, Lucena, it is the most populous region in the Philippines, according to the 2020 census (PSA), with over 16.1 million inhabitants.

The name of the region is an acronym of its five component provinces: Cavite, Laguna, Batangas, Rizal and Quezon.

In 1902, Macario Sakay, a veteran Katipunan member, established the Tagalog Republic in the mountains of Rizal.

Ultimately, Sakay's Tagalog Republic ended in 1906 when he and his men were betrayed under the guise of holding a national assembly aimed at the self-determination of the Filipino people.

[13] One obvious reason for creating the sub-province was the area's isolation from the rest of Quezon Province: there were no direct links to the rest of the province and much of the terrain was mountainous and heavily forested, which made the area relatively isolated, and its distance from Quezon's capital Lucena.

[18] On the other hand, Lucena is home to most of the branches of governmental agencies, businesses, banks and service facilities in the region.

Each province in the region is composed of different environments, ranging from low coastal areas to rugged mountainous ones.

Historically a site of great strategic importance, Corregidor is found at the mouth of Manila Bay and is under the jurisdiction of Cavite City.

Laguna is also home to Mount Makiling, a dormant volcano near Los Baños reputed for its mystical properties.

Batangas borders Cavite via Mount Pico de Loro, known for the views that could be found in its summit.

Rizal is situated north of Laguna de Bay, and consists of a mixture of valleys and mountain ranges, with flat low-lying areas in the western portion of the province near Manila.

The eastern portion of Rizal has hills and ridges which form part of the Sierra Madre range.

The southern part also consists of the Bondoc Peninsula, sandwiched between the Tayabas Bay and Ragay Gulf.

[22] On August 7, 2000, the municipality of Los Baños, Laguna, was declared as a "Special Science and Nature City of the Philippines"[23][24] through Presidential Proclamation No.

349[25] in recognition of its importance as a center for science and technology, being home to many prestigious educational, environmental and research institutions.

Due to the region's proximity to Metro Manila, a large amount of urbanization has taken place over the years.

Cavite and Laguna in particular are sites of manufacturing and high-tech industries, with companies like Intel and Panasonic setting up plants in the region.

Batangas, meanwhile, is home to a large pineapple and coconut industry, which is used to make barong tagalogs and lambanog.

Quezon's towns such as Tayabas City, Mauban and Infanta are also known producers of commercialized native liqueurs such as lambanog and tuba.

Due to their proximity to large bodies of water, Laguna and Batangas also have sizable fishing industries.

The Minor Basilica of Saint Michael Archangel is the religious testaments of the Tayabenses and declared as National Cultural Treasures of the Philippines, the Casa Comunidad de Tayabas, the former office of the then President Manuel Luis Quezon and the place where Hermano Pule was sentenced to death, and the Malagonlong Bridge and the 9 other century-old Spanish arch type and National Cultural Treasure bridges.

Devotees and pilgrims also visit Lucban's Kamay ni Hesus Shrine, which has a 50-foot statue of the Ascending Christ on top of a hill.

The Pan-Philippine Highway is an important road that crosses through Laguna, Cavite, Batangas, and Quezon, serving as a gateway to the southern parts of Luzon.

All the aforementioned expressways also help accommodate the inter-modal traffic between Calabarzon and Metro Manila, serving as a faster, more viable alternative compared to primary highways that directly cross municipal and city centers.

The Laguna Lake Highway, a joint project of DPWH NCR and Region IV-A, is the widening/rehabilitation at Taytay, Rizal segment, a 3.34-kilometer road.