If you happened to compare two population charts side by side, you might notice something striking:
in 2024, Vietnam appears with its familiar 63 provinces and centrally governed cities, but in 2025, a similar chart shows only 34 administrative units.

This is neither a data error nor missing information. It is the direct outcome of a large-scale administrative restructuring implemented nationwide.

In this blog post, I aim to unpack the story behind that visualization:
why the mergers occurred, what policy motivations drove them, and what insights we can extract from the resulting data. This is not merely a story about numbers—it is a narrative about governance, demographic change, and national development strategy.

To illustrate this transformation, we use a specialized visualization technique: the Radial Tree Map—a circular, hierarchical diagram particularly well suited for administrative data.

Why Use a Radial Tree Map for Administrative Data?

Several visualization types can represent hierarchical structures—such as traditional tree diagrams, organizational charts, or geographic maps. However, the radial tree offers distinct advantages for this specific case.

A Unified View of the Entire System

All provinces and cities—before and after restructuring—are displayed within a single circular framework. This immediately conveys that:

The consolidation was a coordinated, nationwide reform, not a series of isolated provincial changes.

Biểu đồ thể hiện sự thay đổi tỉnh/thành Việt Nam trong năm 2025

Regional Identification Through Color Encoding

The chart uses three distinct color palettes corresponding to Vietnam’s major regions:

• Northern Vietnam → dark brown
• Central Vietnam → orange
• Southern Vietnam → yellow

With a single glance, viewers can identify which region experienced the most significant administrative changes.

Clear Hierarchical Structure

The visualization is organized into three levels:

• Inner nodes → Region (North, Central, South)
• Middle nodes → Implementation milestone (here, 01 July 2025, the effective date of mergers and renamings)
• Outer ring → Provinces and cities after restructuring

Conceptually, this structure resembles:

“Standing at the center and observing the entire country unfold in three directions.”

How to Read the Chart: Three Simple Steps

Step 1: Identify the Region by Color

• Yellow → South
• Orange → Central
• Brown → North

This is the fastest way to locate the province or city of interest.

Step 2: Follow the Connecting Paths Inward

Each link reveals:

• Which regional group the new province belongs to
• How many former provinces or cities were merged to form it

Step 3: Locate Converging Nodes

When multiple branches converge into a single outer node, it indicates a new administrative unit formed through consolidation.

Visual Examples and Key Observations

1. Regional Distribution

• Northern Vietnam displays the highest density of nodes, reflecting its historically larger number of provinces.
• Central Vietnam appears more compact, occupying a smaller arc of the circle—highlighting its comparatively lower administrative density.
• Southern Vietnam, marked in yellow, spans a wide arc, illustrating its broad geographic footprint and dynamic urban structure.

2. Administrative Changes: Mergers and Boundary Adjustments

A notable example is the new Can Tho City, established through the merger of:

• Hau Giang Province
• Soc Trang Province
• The former Can Tho City

Sự thay đổi tên/sát nhập của thành phố Cần Thơ (ảnh minh họa)

Interactive Features of the Radial Tree Map

  A key strength of the Radial Tree Map lies in its multi-level interactivity.

• Clicking on a province triggers a tooltip displaying essential information:
  province name, effective date, region, and number of child nodes.
• Clicking again expands the hierarchy, revealing:
  • Original provinces
  • Historical splits and mergers
  • Associated timeline milestones

This “layer-peeling” interaction allows users to explore complex administrative histories progressively, avoiding information overload while preserving logical continuity.

Key Insights from the Visualization

The post-merger administrative structure of Vietnam after 01 July 2025 highlights clear regional contrasts:

• Southern Vietnam, characterized by rapid urbanization, experienced the most significant consolidation—reflecting efforts to streamline local governance and improve administrative efficiency.
• Central Vietnam underwent more balanced adjustments, focusing on boundary rationalization and scale optimization.
• Northern Vietnam saw fewer mergers, preserving many traditional provinces and demonstrating a comparatively stable administrative structure.

These differences illustrate not only a region-specific policy approach, but also the distinct development priorities shaping Vietnam’s administrative reform.

Conclusion

The administrative restructuring effective 01 July 2025 represents a major milestone in Vietnam’s effort to streamline governance and enhance local administrative efficiency.

While the scale and nature of change vary across regions, the common objective remains clear: building a more responsive, efficient, and development-oriented administrative system. These reforms lay a critical foundation for future socio-economic policies and reflect a strategic alignment between governance structures and regional development dynamics.