The Kocaeli Subregion (Turkish: Kocaeli Alt Bölgesi) (TR42) is a statistical subregion in Turkey.

Kocaeli Subregion Kocaeli Alt Bölgesi
Subregion
Country	Turkey
Region	East Marmara
Area
• Subregion	20,402 km2 (7,877 sq mi)
Population  (2013)
• Subregion	3,448,702
• Rank	6th
• Density	170/km2 (440/sq mi)
• Urban	3,148,994
• Rural	299,708

Provinces

• Kocaeli Province (TR421)
• Sakarya Province (TR422)
• Düzce Province (TR423)
• Bolu Province (TR424)
• Yalova Province (TR425)

See also

• NUTS of Turkey

External links

• TURKSTAT (in English)

Sources

• ESPON Database