During the reign of Reza Shah in September 1929, following the approval of the Cabinet of the time, 'Hossein-Abad' village was renamed to 'Ilam' "to commemorate the magnificence and glory of the ancient civilization of Elam.

[18] During the reign of the Medes, Achaemenids, Seleucids and Parthians, owing to its proximity to the districts of Hamadan, Kurdistan, Kermanshah, Lorestan and, most notably, Susa, the area and its settlements took on importance.

During the Sassanid era, the present-day Ilam was composed of two states: Mehrjanqazaq in the east, which was the modern day Darreh Shahr and Masbasan in the west.

The 1937 political division law did not last long and a while later on January 9, 1938, an amendment was passed which divided the country into 10 province and 49 counties.

As a border province, Ilam was a constant target for the Iraqi bombing campaign and suffered heavily in terms of economic infrastructure.

Because of this, it is divided into two distinct natural areas; The northern and eastern parts are mountainous, whereas the southwest is covered with low plains that extend to the Iraqi and Khuzestan borders.

The highest point in the province, Kan Seifi peak with 2,775 m (9,104 ft) above sea level, is part of Kabir Kouh range.

[27][28][29] Other major mountains include: Contrary to the north, the south and southwestern part of the province is covered with low-lying plains with elevation varying between 50 and 300 m (160 and 980 ft) above sea level.

Despite receiving little precipitation, large areas of these low lands, notably Dehloran, Musian and Dasht Abbas, are cultivated owing to a combination of factors such as rivers flowing from the mountains to the east, dams and irrigation networks.

Due to its geographical location, natural conditions and the diversity of its habitats, Ilam province is home to 32 mammals and 183 birds.

These trees are usually found in the rain forests of Northern Iran, but surprisingly grow in this small patch of land in "Lart Valley" near Badreh.

And two nationally registered natural heritage sites:[37] One of the largest landslides in the eastern hemisphere and world is believed to have occurred in Ilam Province, more specifically, in the Kabir Kuh anticline at Gorz-e Langar in Darreh Shahr county.

[39][40][41] Due to the influence of various factors such as altitude, proximity to the Arabian desert, the plains of Khuzestan and Iraq, the climate of the province is very diverse.

Different atmospheric systems affect the province, causing fall, winter, spring, and occasionally summer precipitation.

The steep slopes of Zagros Mountains, soil type, lack of vegetation are among some of the reasons why Ilam province is prone to flooding.

Moreover, majority of communities in Ilam province are located in the floodplains, at the foothills of mountains, on river banks and near sources of water, so there is always risk of flooding with potential human and financial costs.

According to the available statistics, Mehran and Dehloran counties are at the highest risk of flooding due to their lower elevation compared to the rest of the province and the subsequent concentration and joining of rivers and streams.

The cities of Mehran and Dehloran are at the highest risk in the province, due to lower elevation and proximity to the deserts of Iraq and Saudi Arabia.

This diversity derives from the geographical location of the province, positioned in the transitional zone between Kurdish and the Southwestern Iranian language bloc.

Kurdish is the dominant language in the cities of Ilam, Mehran, Eyvan, Abdanan, Sarableh, Lumar and Pahleh, and Cheshmeh-ye Shirin Shah Ahmad is the southern-most Kurdish-speaking settlement in the province.

[11] Luri is spoken in the southern parts of the province and is the predominant language in Murmuri, Haft Cheshmeh and many smaller villages.

[11] Arabic is spoken in smaller settlements near the border to Khuzestan Province including in Shahrak-e Zu ol Faqari.

Throughout history, many people have settled and ruled in the region and as the result, today, Ilam is inhabited by Kurds, Lurs, Laks and Arabs.

Upon its creation by Sahar Chalanghar, a resident of Zanjireh village of Sarableh county, Ilam's embossed kilim became popular both in Iran and the world.

Some of the local traditional dishes are:[60][61]The highest government authority of the province is the governor-general, who is appointed by the Minister of Interior given cabinet approval.

Most economic activities in the province are focused on agriculture and animal husbandry in the rural communities; and, skilled trades, public and private services in urban areas.

Ilam is the bottom 3rd province in the country in terms of crop yield at 3.14 tons per hectare, only surpassing Kohgiluyeh and Kurdestan.

[63] The farming lands of Ilam, like its geography, are divided; The northern and eastern parts of the province are mountainous and despite the presence of water resources, cultivable lands are limited to inter-mountain plains, foothills and river banks; On the contrary, the hot climate plains of the south and southwest such as Hojandan-Dasht, Amir-Abad, Mehran, Mosian, Dehloran and Dasht-Abbas, are large in size but limited in water resources.

The most important oil and gas fields in Ilam are: Dehloran, Tang-e Bijar, Chashmeh Khosh, Paydar-e Gharb, Azar and Danan.

[82][83][84] One of the most known athletic figures of Ilam province is Mojtaba Maleki, a two times gold medalist in World Powerlifting Championships in 2017 and 2018.