Mykolaiv Oblast (Ukrainian: Миколаївська область, romanized: Mykolaivska oblast, IPA: [mɪkoˈlɑjiu̯sʲkɐ ˈɔblɐsʲtʲ]), also referred to as Mykolaivshchyna (Ukrainian: Миколаївщина, IPA: [mɪkoˈlɑjiu̯ʃtʃɪnɐ]), is an oblast (province) of Ukraine. The administrative center of the oblast is the city of Mykolaiv. At the most recent estimate, the population of the oblast stood at 1,091,821 (2022 estimate).

Historically, at various times, the territory was ruled either entirely or partly by Scythia, ancient Greeks, Old Great Bulgaria, Khazars, Kipchaks, the Mongol Empire, Lithuania, the Crimean Khanate, the Ottoman Empire, Poland, and Russia. Historic cities of greatest importance were ancient Olbia and the late medieval port city of Ochakiv. In the late 17th and 18th centuries the tripoint of three early modern great powers, the Polish–Lithuanian Commonwealth, the Ottoman Empire and Russia, was located at the site of the current second-largest city of Mykolaiv Oblast, Pervomaisk, a city formed by the merger of the former Polish town of Bohopol, Russian town of Olviopol and Ottoman village of Holta.

The oblast was established within Soviet Ukraine in 1937. During World War II, it was occupied by Germany in 1941–1944.

During the 2022 Russian invasion of Ukraine, the Russian army invaded the province from Kherson Oblast, attacking as far northwest as Voznesensk. They were repulsed at Voznesensk, and their attempt to take Mykolaiv failed. From April 2022, almost all of the province was under Ukrainian control, apart from the extreme south-east and the Kinburn peninsula. When Russia annexed Kherson Oblast in September 2022, it incorporated the occupied areas of Mykolaiv Oblast. A Ukrainian military official announced a Russian withdrawal from Mykolaiv Oblast on 10 November 2022.

On 4–5 July 2022 during an international Ukraine Recovery Conference (URC 2022) in Lugano, Switzerland pledged to support the rebuilding of Mykolaiv region.

Mykolaiv Oblast is located in the southern half of Ukraine. Its area (24,600 km²) comprises about 4.07% of the total area of Ukraine.

Mykolaiv Oblast borders upon Odesa Oblast in the west-southwest, Kirovohrad Oblast in the north, Dnipropetrovsk Oblast in the northeast, and Kherson Oblast on the southeast.

To the south, the oblast is also bordered by the Black Sea. To Mykolaiv Oblast belong Kinburn Peninsula, Berezan Island in Black Sea, Pervomaisky Island in Dnieper Estuary.

Historically, it is located in Yedisan (central and southern parts), Zaporizhzhia (northern part) and Podolia (north-western part). Pervomaisk, the second largest city of the province, is located at the tripoint of the three historic regions.

In regards to relief, Mykolaiv Oblast is a plain that gently slopes in southern direction. Bigger portion of the territory lays within Black Sea Lowland. To the north there are spurs of Podolian and Dnieper uplands. Among major valuable deposits and minerals there are nickel, uranium ores, granite, gneiss, quartzites.

The climate is moderately continental with a mild winter of small snow amount and hot arid summer.

In the territory of the region are eighty-five rivers that belong to basin of the Black Sea. Among main rivers there are the Southern Bug (Boh) which splits the oblast into eastern and western parts, Inhulets, and Berezan.

The following historic-cultural sites were nominated for the Seven Wonders of Ukraine or Seven Natural Wonders of Ukraine.

• Olbia, an ancient ruins of Greek colony near Ochakiv
• Black Sea Biosphere Reserve, located near Kinburn peninsula
• Granite-steppe lands of Buh, a landscape park located up north towards Podolia
• Inhul River Park, a landscape park in eastern part of the region
• Tylihul landscape park, on the administrative border with Odesa Oblast
• Dykyi Sad archaeological site (Wild Garden) in the city of Mykolaiv

The estimated population was 1.2 million people in 2005. The greater part of the oblast's population resided in urban type settlements (66%), with the remainder residing in agricultural areas. Also, almost 60% of the urban population resided in Mykolaiv, the industrial, cultural and administrative center of Mykolaiv Oblast.

As of 2021, the total population of the oblast was estimated at 1,108,394 inhabitants, with 761,278 (68.7%) residing in urban areas and the remaining 347,116 (31.3%) living in rural areas. The city of Mykolaiv, home to 341,123 residents, constituted 68.8% of the urban population of Mykolaiv Oblast.

The oblast's population density is one of the lowest in Ukraine – 45 inhabitants per square kilometre (120/sq mi). Mykolaiv Oblast contains 2.7% of the population of Ukraine, by percentage share ranking 19th among Ukrainian oblasts and territories.

0-14 years: 14.7% (male 88,668/female 83,434)

15-64 years: 70.7% (male 396,342/female 432,808)

65 years and over: 14.6% (male 56,527/female 114,987) (2013 official)

total: 39.7 years

male: 36.3 years

female: 42.9 years (2013 official)

The oblast has a multi-ethnic composition; people of more than 100 ethnicities (national groups) live in the oblast. The most common language in the oblast is Ukrainian; the second most common language is Russian. In the city of Mykolaiv the most common language is Russian.

At the time of the 2001 census, the oblast had 1,269,900 permanent residents. Of these:

• 1,251,100 (99.1%) had Ukrainian citizenship.
• 6,400 had citizenship of CIS countries.
• 10,200 had citizenship of other countries.
• 4,200 were without citizenship.
• 1,000 who did not specify their citizenship.

Ethnicity ("Nationality")	Permanent residents 2001		Mother Tongue 2001			Permanent residents 1989	Mother Tongue 1989
	Number	%	Ukrainian	Russian		%	Ukrainian	Russian
All ethnicities	1,269,900	100.0%	69.2%	29.3%		100.0%	64.2%	33.8%
Ukrainian	1,034,400	81.9%	82.4%	17.5%		75.6%
Russian	177,500	14.1%	6.2%	93.7%		19.4%
Moldovan	13,200	1.0%	28.5%	16.8%		1.3%
Belarusian	8,400	0.7%	21.8%	58.5%		1.1%
Bulgarian	5,600	0.4%	16.9%	53.2%		0.5%
Armenian	4,300	0.3%	7.1%	35.8%		0.1%
Jewish	3,300	0.3%	10.1%	87.4%		0.9%
Korean	1,800	0.1%	6.3%	70.8%		0.0%
Azerbaijani	1,500	0.1%	8.1%	33.3%		0.1%
Gypsy (Roma)	1,400	0.1%	38.7%	15.2%		0.1%
Polish	1,300	0.1%	47.4%	44.1%		0.2%
Tatar	1,300	0.1%	7.3%	73.5%		0.1%
German	1,200	0.1%	26.8%	67.7%		0.1%
Other	7,700	0.7%	13.8%	37.3%		0.5%

Mykolaiv Oblast formed in September 1937. it is subdivided into various areas, mostly raions. The subdivisions changed in 2020.

On 18 July 2020, the number of Mykolaiv Oblast subdivisions was reduced to four raions. These are:

1. Bashtanka (Баштанський район), the center is in the town of Bashtanka;
2. Mykolaiv (Миколаївський район), the center is in the city of Mykolaiv;
3. Pervomaisk (Первомайський район), the center is in the town of Pervomaisk;
4. Voznesensk (Вознесенський район), the center is in the town of Voznesensk.

Before July 2020, Mykolaiv Oblast was subdivided into 24 regions: 19 raions (administrative districts) and 5 city municipalities (mis'krada or misto), officially known as territories governed by city councils which are directly subordinate to the oblast government.

Name	Ukrainian Name	Area (km)	Population census 2015	Admin.center	Urban Population Only
Mykolaiv	Миколаїв (місто)	260	493,860	Mykolaiv (city)	493,860
Pervomaisk	Первомайськ (місто)	25	66,677	Pervomaisk (city)	66,677
Voznesensk	Вознесенськ (місто)	23	35,520	Voznesensk (city)	35,520
Yuzhnoukrainsk	Южноукраїнськ (місто)	24	40,353	Yuzhnoukrainsk (city)	40,353
Arbuzynka Raion	Арбузинський (район)	969	20,198	Arbuzynka	8,543
Bashtanka Raion	Баштанський (район)	1,706	37,721	Bashtanka	12,640
Berezanka Raion	Березанський (район)	1,378	23,409	Berezanka	4,120
Bereznehuvate Raion	Березнегуватський (район)	1,264	20,387	Bereznehuvate	7,742
Bratske Raion	Братський (район)	1,129	18,037	Bratske	5,325
Domanivka Raion	Доманівський (район)	1,458	25,500	Domanivka	6,137
Kazanka Raion	Казанківський (район)	1,349	19,745	Kazanka	7,207
Kryve Ozero Raion	Кривоозерський (район)	814	24,905	Kryve Ozero	7,823
Mykolaiv Raion	Миколаївський (район)	1,430	30,448	Mykolaiv (city)	N/A *
Novyi Buh Raion	Новобузький (район)	1,243	31,199	Novyi Buh	15,566
Nova Odesa Raion	Новоодеський (район)	1,428	33,602	Nova Odesa	12,108
Ochakiv Raion	Очаківський (район)	1,500	29,949	Ochakiv	14,489
Pervomaisk Raion	Первомайський (район)	1,319	30,275	Pervomaisk (city)	N/A *
Snihurivka Raion	Снігурівський (район)	1,350	40,420	Snihurivka	12,870
Veselynove Raion	Веселинівський (район)	1,245	23,161	Veselynove	8,060
Vitovka Raion	Вітовській (район)	1,460	50,565	Mykolaiv (city)	N/A *
Voznesensk Raion	Вознесенський (район)	1,392	30,562	Voznesensk (city)	N/A *
Vradiivka Raion	Врадіївський (район)	801	17,611	Vradiivka	8,391
Yelanets Raion	Єланецький (район)	1,018	15,530	Yelanets	4,912
Total Oblast	Миколаївська (Область)	24,585	1,159,634		791,227

Note: Asterisks (*) Though the administrative center of the rayon is housed in the city/town that it is named after, cities do not answer to the rayon authorities only towns do; instead they are directly subordinated to the oblast government and therefore are not counted as part of rayon statistics.

At a lower level of administration, these district-level administrations are subdivided into:

• Settlements — 922, including:
  • Villages — 896;
  • Cities/Towns — 21, including:
    • Cities of raion subordinance — 4 (Bashtanka, Novyi Buh, Nova Odesa and Snihurivka);
    • Urban-type settlement — 17;
• Selsovets — 287.

The local administration of the oblast is controlled by the Mykolaiv Oblast Rada. The governor of the oblast is the Mykolaiv Oblast Rada speaker, appointed by the President of Ukraine.

• Along the coast, there are several ports and the Mykolaiv International Airport.
• The region's railway network and infrastructure is part of the Odesa Railways.
• Through the region passes European route E58 and European route E95.
• The city of Mykolaiv is known for several of its shipyards that existed since the 19th century.
• South Ukraine Nuclear Power Plant
• Agrarian company Nibulon
• Mykolaiv Observatory

During the 1991 referendum, 89.45% of votes in Mykolaiv Oblast were in favor of the Declaration of Independence of Ukraine. A survey conducted in December 2014 by the Kyiv International Institute of Sociology found 2.1% of the oblast's population supported their region joining Russia, 95.5% did not support the idea, and the rest were undecided or did not respond.

• 
  Mykolaiv Observatory
• 
  Lutheran church in Mykolaiv
• 
  Old mill in Snihurivka
• 
  South Ukraine Nuclear Power Plant
• 
  Kinburn Spit
• 
  Bug River rapids
• 
  Aktove canyon
• 
  Yelanets Steppe Nature Reserve

• Subdivisions of Ukraine
• Kherson Governorate
• Lysa Hora

• State Administration of Mykolaiv Oblast - official site (in Ukrainian, Russian, and English)
• Information Card of the Region - official site of the Cabinet of Ministers of Ukraine